94 3.4L DOHC won't start, nothing but FAIL. What now?

[GnatGoSplat]

94 Cutlass convertible with 3.4L DOHC has been down a month, took weeks to get all the parts, and many hours of back-breaking work later, it's all back together.

 

...but it won't start.

 

What caused it to die in the first place is the FPR went bad and it flooded everything full of fuel. Made a thread about it here:

http://www.w-body.com/showthread.php/80649-3-4-DOHC-Fuel-Pressure-Regulator-Adventures-and-questions-saving-my-brake-booster

 

Went ahead and replaced spark plugs, valve cover gaskets, plug wires, plugs, oil manifold gasket, and lower intake manifold gasket while I was at it.

 

Back to the problem:

 

I had checked the fuel pressure before I put it back together. Ohm'd the injectors, all the same at 12.4-ohms. Just over 40psi with the pump running, nothing dripping out of any injectors, nothing coming out of the FPR vacuum line. I thought that part was fine.

 

I noticed now the fuel pressure bleeds off pretty quick and then slows down at 10psi. Weird. What would cause this, if FPR doesn't leak? Usually means leaky injectors in my experience, but no fuel came out of them when I tested it earlier. Wish I'd checked pressure bleed off time when I had the fuel rail loose, but either I didn't think of it or it seemed normal enough I didn't notice.

 

It kind of acts like it wants to start when I crank it, but it doesn't. I noticed a little bit of smoke underhood. Not sure where it's coming from, just like a light mist of smoke everywhere.

 

Also, cranking sounds kind of weird. More whiney. Is it possible fuel getting in a cylinder could have made it jump time, like if it had been fuel hydrolocked and I didn't realize it? I take it this would show on a compression tester? I guess I'd need some kind of DOHC adapter to get a compression tester to fit. Is there any that is an ideal length for the 3.4 DOHC?

 

I'm so frustrated and depressed. Sadly, this might be the end of the line for the car. I may have to junk it or sell it cheap and just buy something else. We were going to sell the car in the next year anyway, but I was hoping I could keep it running till we find something else. Oh well.

[RobertISaar]

FPR could be leaking(internally) to cause that pressure drop.

[GnatGoSplat]

If FPR were leaking internally, would it still start and run if it can maintain fuel pressure while cranking? I think it's about 43psi when cranking.

[RobertISaar]

i would assume if it maintains pressure while cranking, it isn't causing that problem, just the leakdown after the pump quits feeding it.

[GnatGoSplat]

Just checked, maintains 43psi continuously while cranking. Just double-checked at the 6-way fuel injector connector to see if maybe I stupidly forgot to plug in an injector or two under the plenum where I can't see them, but nope. Looks like I got 'em all.

 

Is it actually possible the belt or cams could have slipped? I seem to recall the cam sprockets aren't keyed to the cams.

[RobertISaar]

i guess the belt could have slipped... having the tone while cranking change was a good indicator that I had to change a broken timing belt on more than a few engines. slipped could certainly do the same.

 

I wouldn't think the cam sprockets themselves would slip... the bolts that hold them down should have plenty of torque to keep them more or less friction locked in place, I would think the belt would stretch/slip/break before the cam sprockets would start spinning.

[GnatGoSplat]

Yep, it seems to have a way more even tone than I remembered, like there is less resistance (less compression) than there should be. I'm guessing a compression tester will tell me all I need to know although I'll need an adapter to use my tester on it since the plugs are way too deep.

[Schurkey]

Do you have spark? Any chance the plugs are fouled? Plug wires installed properly? When you had the plugs out, after the FPR died and filled the engine with gasoline, did you crank the engine to blow the gasoline back out of the cylinders?

 

I bought the OTC compression adapter; but I don't think I've used it on a 3.4L yet. I don't know if it's long enough. It's also Taiwanese--the days of OTC doing anything in this country seem to be over. Bosch bought OTC and have essentially ruined the company.

http://www.amazon.com/OTC-5603-Compression-Tester-Connector/dp/B000R5ARJ2/ref=sr_1_16?ie=UTF8&qid=1416812369&sr=8-16&keywords=OTC+compression

 

First Guess: either there's no spark or the plugs are fouled (again) from excess fuel in the cylinders.

 

Second Guess: The cams are still "in time" if the belt is OK.

[GnatGoSplat]

Located my inductive timing light this morning, so I was able to check spark.

 

Only had time to check front bank, plugs 2, 4, 6, before I had to run to work, but waste spark so rears probably work. All appear to spark fine, I'd guess spark is 500ms apart. If starter cranks 200rpm, that should be 3.33rps. If coil fires twice per rev, that should be 6.66 sparks per second or 150ms apart. Not sure if my math is correct, but maybe the starter is cranking too slow? A few times it kind of acts like it might start, but never does, so I kind of doubt that's the problem but I can try jump-starting it. It's actually acting very similar to the way it was when it first died.

 

Plugs shouldn't be fouled, they're brand new, gapped to spec 0.045, AC Delco R42LTSM.

 

Plug wires should be installed properly, I carefully labeled them all and quadruple checked the coils. They're hooked up 1-4-3-6-2-5, same as FSM specifies and same as before (took lots of "before" pics to make sure). I've seen pics of OEM coils with numbering 1-4-6-3-2-5, but waste spark so it shouldn't matter.

 

Yes, I did crank the engine to blow gasoline back out of the cylinders and also peered into the plug holes with a flashlight to make sure they were dry inside.

 

That's a nice looking adapter, don't think it'll work on my compression tester though, mine is a cheapie from the auto parts store retail floor and doesn't have a quick-disconnect fitting.

[Galaxie500XL]

Quick and dirty way to check the cam timing would be to check with the engine at TDC, and see if the flats on the cams are pointing up, You could pull the front valve cover and check those pretty easily. Remember, if they aren't pointed straight up at TDC, you may have to rotate the engine by hand an additional turn....the flats should both be pointing up, and parallel to the cam carrier surface on one of those turns. Rears, of course, would require removing the plenum in order to remove the valve cover---I wouldn't bother with them unless I saw a problem with the fronts. If the fronts are more or less pointed right, at the very least the car should start. I'm guessing you've already watched how the belt is moving while cranking with the front inspection cover removed...

 

Located my inductive timing light this morning, so I was able to check spark.

 

Only had time to check front bank, plugs 2, 4, 6, before I had to run to work, but waste spark so rears probably work. All appear to spark fine, I'd guess spark is 500ms apart. If starter cranks 200rpm, that should be 3.33rps. If coil fires twice per rev, that should be 6.66 sparks per second or 150ms apart. Not sure if my math is correct, but maybe the starter is cranking too slow? A few times it kind of acts like it might start, but never does, so I kind of doubt that's the problem but I can try jump-starting it. It's actually acting very similar to the way it was when it first died.

 

Plugs shouldn't be fouled, they're brand new, gapped to spec 0.045, AC Delco R42LTSM.

 

Plug wires should be installed properly, I carefully labeled them all and quadruple checked the coils. They're hooked up 1-4-3-6-2-5, same as FSM specifies and same as before (took lots of "before" pics to make sure). I've seen pics of OEM coils with numbering 1-4-6-3-2-5, but waste spark so it shouldn't matter.

 

Yes, I did crank the engine to blow gasoline back out of the cylinders and also peered into the plug holes with a flashlight to make sure they were dry inside.

 

That's a nice looking adapter, don't think it'll work on my compression tester though, mine is a cheapie from the auto parts store retail floor and doesn't have a quick-disconnect fitting.

Edited November 24, 2014 by Galaxie500XL

[GnatGoSplat]

Good tip, I'll be sure to check that. I did watch the belt with the rear inspection cover removed and had my wife crank the engine, but that was when I had the plugs out and it looked fine at the time. Hopefully I can get a tool on the crankshaft pulley bolt, though it looked pretty tight in there.

[Galaxie500XL]

The crank pulley bolt isn't too bad to get to, but you may have to get creative on what socket you use to get enough clearance. Unfortunately, having done two belt replacements on my LQ1 within 3 years, I got all too good at it.

Good tip, I'll be sure to check that. I did watch the belt with the rear inspection cover removed and had my wife crank the engine, but that was when I had the plugs out and it looked fine at the time. Hopefully I can get a tool on the crankshaft pulley bolt, though it looked pretty tight in there.

[GnatGoSplat]

Couldn't get a long enough wrench on the crank pulley, gonna have to buy a shallow depth 15mm 1/2" drive socket. Only thing that would fit is a 3/8" socket and ratchet, which is too small for me to be able to rotate the engine easily and precisely (I can push on the ratchet with all my might and move the engine in jerks and spurts, but not going to be able to move it precisely to TDC that way).

 

Anyway, I thought I'd try to eliminate slow cranking as a problem and jump-started it with the truck. It did some more weird stuff. After letting it crank for several seconds and failing to start (but sort of chugging a bit like it kind of wanted to), 2 times in a row the starter would sound like it turned the engine a bit and then just immediately stop. As if it was hydrolocked or something. Pulled the FPR vacuum line to verify no fuel coming out of it. After letting it sit for a few seconds it was then able to crank again, but very weird.

 

So now I'm wondering if I really do have a severely leaking injector too, so severely leaking that it bleeds off pressure almost immediately and flooding a cylinder. Tried to narrow down the cause of fuel pressure bleedoff by squeezing the return line. If pressure still bleeds off, that would eliminate the FPR and mean it's either a leaky injector or fuel pump valve, right? Either I suck at squeezing, or it's one of those because the pressure still bled off. Tried to eliminate the fuel pump by squeezing the feed line after building pressure. As soon as I turn off the pump, it still bleeds off quickly, but when I release the feedline it jumps down about 10psi. Can't really tell if I just suck at squeezing these fuel lines (they are very firm for rubber lines, and I'm sure the cold doesn't help). At any rate, if one injector is bleeding off pressure, I'd think it would still run, though with a severe miss.

 

So confused.

[55trucker]

^ If you do indeed have a leaking injector then that cylinder will be washed with fuel, pull all the plugs & look for the fouled plug.

 

When you mentioned that you *checked the fuel pressure* did you have a proper fuel pressure gauged screwed onto the schrader valve in the fuel rail?, and if so can you *see* the gauge losing pressure on the dial as you watch it?

[GnatGoSplat]

Finally received the DOHC adapter for my compression tester. Took 2 full weeks on an in-stock item, thanks Amazon. Managed to test compression on the front 3.

 

2 = 70psi

4 = 85psi

6 = 30psi

 

Was not able to get the tool on the rear bank. I'll have to pull the plenum to check the rear, but the readings I've got don't look very good at all assuming my starter cranking speed is sufficient. Didn't realize I'd probably need 2 DOHC adapter tubes to attach my compression tester to the rears without pulling the plenum. My guess from the 2-4 readings is engine probably jumped time, those 2 readings are close. However, what's up with 6? It's quite a bit lower than the other 2.

 

Quick and dirty way to check the cam timing would be to check with the engine at TDC, and see if the flats on the cams are pointing up, You could pull the front valve cover and check those pretty easily.

 

From my compression results, I'm guessing at the very least the engine has jumped time. Dan, how do you know when the crank pulley is at TDC? I'm not sure what to look for in terms of timing marks and couldn't find anything in the FSM. Do I have to pull the large plastic access cover to see them? I figure if I can tell for sure it's jumped time, might as well pull the plenum and check compression on the rear bank just to see how bad it is.

 

^ If you do indeed have a leaking injector then that cylinder will be washed with fuel, pull all the plugs & look for the fouled plug.

 

When you mentioned that you *checked the fuel pressure* did you have a proper fuel pressure gauged screwed onto the schrader valve in the fuel rail?, and if so can you *see* the gauge losing pressure on the dial as you watch it?

 

Plugs don't look significantly fouled. Only the #3 plug has some dry deposits on the electrode. The others are relatively clean. I've attached a pic.

Yes, I checked fuel pressure with a proper fuel pressure gauge screwed into the schrader and I could see the gauge losing pressure quickly. Maybe leaking at the pulsator? I'm thinking I've got bigger problems than the fuel system though.

[mfewtrail]

Shawn, use the pictures here for crank pulley TDC reference: http://60degreev6.com/content.php/67-3-4-DOHC-Camshafts

 

 

All those compression readings are on the low side, but cylinder 6 is dramatically lower than the others. Did you have the throttle open 100% as you performed the test? If your cam timing checks out, you're likely dealing with sealing issues on number 6 now since it was the one that was completely filled with fuel from your previous thread.

[55trucker]

Finally received the DOHC adapter for my compression tester. Took 2 full weeks on an in-stock item, thanks Amazon. Managed to test compression on the front 3.

 

2 = 70psi

4 = 85psi

6 = 30psi

 

 

 

That 70 psi reading is approx 100lbs short of where a healthy DOHC should be, it's no wonder you couldn't get any *fire in the hole*, as stated....timing issue

you may have no injector issues at all, the loss showing on the fuel gauge tester could be fuel line related as you earlier thought, try the gauge again but this time completely pinch off the flexible return line off the rail & as well disconnect the vacuum line at the regulator & close/seal off the port & see if the gauge holds pressure, with a key on *no run* you should have approx 48lbs on the gauge under normal conditions, pinch off the return line & that figure should go up.

[GnatGoSplat]

Shawn, use the pictures here for crank pulley TDC reference: http://60degreev6.com/content.php/67-3-4-DOHC-Camshafts

 

 

All those compression readings are on the low side, but cylinder 6 is dramatically lower than the others. Did you have the throttle open 100% as you performed the test? If your cam timing checks out, you're likely dealing with sealing issues on number 6 now since it was the one that was completely filled with fuel from your previous thread.

 

I think I can see the TDC mark on the timing cover casting, but my crank pulley doesn't look like the one in the pic. Mine looks like this one:

http://cliff.hostkansas.com/images/2011/timing_belt.jpg

Is there some kind of cover on the pulley I need to remove?

 

If jumped timing were the only problem, wouldn't all the cylinders still be pretty close (within 20%), but with low compression?

Yes, I did have the throttle open 100%. I checked cyl #6 3 times because it was so far off from the other two. First time I actually only got about 10psi and 20psi the next time, that was just cranking and counting to 10. When my wife got home, I had her crank with pedal to the floor and had her stop when the gauge quit moving. What could explain cyl #6's low reading? Slightly bent or warped valves?

It actually was cyl #1 whose intake port was full of fuel. Wasn't able to test any of the back 3, unfortunately.

 

Would like to verify jumped timing using Dan's method before bothering to pull the plenum and checking compression on the back 3.

 

If it hydrolocked hard enough to jump timing... that in itself doesn't instill much optimism.

[Schurkey]

In MY garage, that thing would get a cylinder leakdown test. Escaping air noise from the throttle body indicates leaking intake valves. Escaping air noise from the tailpipe indicates leaking exhaust valves. Escaping air from the radiator indicates defective head gasket or cracked castings.

 

Some escaping air noise from the crankcase is normal, you'll need to use the leakdown tester equipment gauge(s) to determine the amount of leakage past the rings--and whether it's an acceptable amount.

[GnatGoSplat]

I've read about leak-down testers and how it's much better than compression testing as it eliminates more variables. Unfortunately, that's probably beyond my tools budget as I don't even have an air compressor. I didn't really notice any escaping air noises.

 

Still need to do what Dan mentioned and confirm jumped timing. Getting ahead of myself, but if I have jumped timing, but all t-belt teeth are intact, all idlers okay, would it be theoretically possible to reset timing by locking cams in TDC position using hold-down tools, compress the hydraulic tensioner to loosen then belt, turn crankshaft to TDC position, then release the tensioner? At least that way I feel like I could better confirm engine condition without spending hundreds of dollars first. Then if it seems like it runs good and compression seems okay, then I would replace the belt proper. I'm guessing there must be a major flaw in that idea?

[GnatGoSplat]

I found the timing marks on the crank pulley. Got it set to TDC.

Pulled the front cam cover and cams are as flat and parallel to the top as they can be. This is very odd and unexpected. So jumped timing doesn't explain the low compression on the front 3. I didn't find any fuel in the front 3 cylinders when I took the plenum off way back when so I didn't really expect valves to be damaged on the front 3. WTF? Maybe the starter is cranking too slow? Perhaps I need to take the battery to get tested.

 

Slow starter doesn't explain why the car won't start at all though, as it sometimes acts like it wants to. Is it possible for only the rear cams to jump timing?

 

UPDATE: Took battery to Wal-mart. Tests good on their fancy tester.

Edited December 15, 2014 by GnatGoSplat

[Schurkey]

Have you verified the accuracy of your compression tester's gauge?

 

Most compression testers that use a quick-coupler fitting in the hose can be connected to a compressed-air supply very easily--then you compare the compression tester gauge to the pressure gauge on the air pressure regulator.

 

Or--test several "known-good" engines to see what sort of pressure they develop on that gauge.

[GnatGoSplat]

IT'S ALIVE!

 

Had a thought about what fuel might do if it floods the cylinders and intake. Was thinking, well, it might dissolve and dislodge any carbon and crud in the combustion chamber and intake itself. Imagining this scenario in my head, I pictured that crud could get into the valve seats and affect sealing, therefore lowering compression enough the car wouldn't start. Read most cars need 90psi cold compression to start and I was only getting 70-85. Read that putting motor oil into the spark plug holes increases compression. Figured it didn't have far to go to make 90psi, surely a little oil could do this, so I dumped a teaspoon of motor oil into each cylinder hoping that would raise compression enough to start and maybe burn off any theoretical crud on the valves and valve seats. This time when I cranked, it still sounded a bit like a freewheeling starter (hardly any compression), although it acted more like it wanted to start than before. I cranked it with the throttle open and after awhile it did start, running like total crap and spewing a huge amount of smoke out the exhaust. It would die when let off the gas. Managed to get it started up again and ran it at high RPM a few times, flooding the entire garage full of smoke, and eventually it evened out. Started it up a couple times afterwards and now the starter sounds normal when cranking (huge difference) and the car starts first time. Had a lot of lifter tick and surging during closed-loop that would cause it to stall while idling, but an oil change cured the lifter tick and a new air filter replacing the filthy old, blackened, previously fuel-soaked one, fixed the surging idle and stalling.

 

Drove the car 13-miles today to try it out. Smoked pretty bad for the first couple blocks, but eventually quit and seems fine so far. Took it up to highway speeds, no problems. I do hear a hissing sound when I accelerate, sounds like it's coming from the driver side underhood, pretty loud with the windows open, not so loud with them shut. I sprayed carb cleaner everywhere and couldn't find a vacuum leak. Maybe the booster is shot? But it seems to stop just fine so I don't know if that could be it. Doesn't seem to affect drivability or idle though.

 

Really didn't think my idea would work, I was pretty floored when it did. Had no interest in pulling the heads, so I was already planning to have to sell it as a non-running car and just had a couple things to try first. Glad one of them panned out!

[Schurkey]

Glad you had success. Beats selling it for scrap.