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TGP help Slow gas guzzler


richiewwhite
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Hey guys out of the w body for a while. I had given the car to my parents to use and they had killed it or my mother had killed it actually. Now having gotten it back I plan on fixing it up. The car is a dog. It is slower then all hell and could never break the tires loose as is. So far. I replaced plugs wires oil change and tensionor and dog bones. It runs the same.Im doing the valve cover gaskets today and did the brakes yesterday. Here are a list of the problems. There is no check engine light on so that makes me think comp is working and so is O2 and all other sensors that would trigger a check engine light. If i stomp the pedal going from a roll about 15mph or so it will try to bog. If i feather it I can get up to higher rpm. Occausionally it shifts really late almost to redline. It shifts good and firm. If Im going on the parkway about 55 or so I try to accelerate but it does not climb over 4200 rpm. I checked for vacum leaks and found nothing. THe dumbby guage in the cluster shows it has vaccum. It idles decent but somtimes if im in park and bounce the rpm off the rev limiter to spool the turbo then let off the idle doesnt drop immediately it will hover around 1500 or so and work its way back down.

 

The gas mileage is ridiculous. When I had the car it would get awesome gas mileage especially on highway(37) crusing about 74 mph. Now The instant ecomny shows usually 9 or less when just cruising and average gas mileage is about 6. I used to have the smell of unburned fuel but that seem to have gone away. any help would be appreciated.

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OK... I tried changing the fuel filter and nothing. Same with the injector cleaner. I did the valve cover gaskets today and cleaned them up pretty nice. Now it doesnt leak any oil which is good but, the car is still a dog.its smoother now but still very very slow especially low end. Still also a gas guzzler averaging about 6-9 driving steady 60mph when it used to be about 32 according to the little sentry system. I had a service engine light come on and I had scanned the codes and only one to come up is a lean condition. Im getting a guage to check my fuel pressure but I dont understand why the car running lean would cause really bad gas mileage. It could very well cure the slowness.

 

What about the ignition coils? I thought it was they either work or they dont. or even weak. But it should cause this bad of gas mileage.

 

This is becoming annoying as Im dumping alot of money into it and it hasnt even come up to the performance it had when I gave the car to my father.

 

Any ideas would be helpful

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Well, my first piece of advice is to click submit once. :lol:

 

Try changing the O2 sensor. That may be faulty and causing a lean condition, and either way it never hurts to put a new OEM sensor in. Contact Jeff M about an OEM part, or I could get you one for fairly cheap. Don't go Bosch as they are shit, OEM is best.

 

Now if that doesn't do it, I would bet it's fuel related. Could be injectors dumping fuel, could be the FPR, could be the pump. Get a tester and check the pressure. Then get back with us. Those are the best places to start, IMO. Good luck.

 

EDIT: May also want to check the vacuum connection at the MAP sensor, which could throw everything off. There are two 13mm bolts holding that and the EVAP SOL on the rear of the upper plenum. Make sure nothing is cracked or disconnected.

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Richie (name?), with the rich condition you describe from bog at take offs and poor gas mileage and the key item the hang-up at around 4,200 rpms its your OEM Crossover Pipe! Sold many pipes to owners and these are very common complaints, until the pipe is replaced. One test though not sure if it always works is to get the engine warmed up to normal temps, pull the ECM fuse for 30 seconds, put the fuse back in and quickly go for a drive to see if you still have those same problems. The o2 may be too fouled as well as your combustion chamber etc but still worth a test, other tests are to pop the hood when the engine is cold, start it up and quickly look under the hood for white smoke around the crossover pipe, smelling for raw exhaust, that would be signs of the crossover pipe leaking, or sooty marks around the metal shield over the crossover pipe.

 

Sorry I did not reply sooner/before you replaced these parts, been working on cutting down trees (125 foot cotton wood), installing air conditioners, taking care of the wife just out of the hospital, you know, normal stuff :lol: that keeps you busy 8)

 

Jeff M

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Ok checked fuel pressure it is constant 35 at idle and goes up to bout 45 at 3k bouncing off the rev limiter. Its much smoother now that I did the valve cover gaskets and found a vaccum leak from the throttle body that goes back to a solenoid it looks like near the back valve cover. It looks nice now but still running bad. I changed the fuel filter and ran injector cleaner through it. It seems like its surging as it slowwly climbs the rpm band. Its stil slow but now it doesnt leak oil which makes me happy and it still sucks gas. I unpluged the O2 sensor and drove it and its the same plugged in or out. also the sensor on the left side of the intake had oil in it. I guess its a manifold air temp sensor. It idles much smoother now that the vaccum line is plugged in. I cant figure this shit out.

 

I wanna take off the coil packs to get them tested but Its raining and im unsure of how many bolts hold in each coil pack. Can they be tested on the car ? like at auto zone? Im not buying coil packs if these are still ok.

 

Need some help with this.

 

On another note how the hell do you compress the rear brake pistons. I broke my C clamp!

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New light on the story. Was driving it and then shut off and checked all the fuses. I got back in the car and it was actually as fast as it used to be spinning the tires down the street in the rain. It is slow then fast then slow again. It seems very sputtery when slow and sometimes has good low end acceleration and then around 4500+ it goes soo slow.

 

I also just had a weird bouncy idle. It would range from about 1000rpm to 500 almost stalling everytime as it bounced.

 

Im not sure if this has anything to do with it but I turned on my defroster and it idles better and as soon as I turn it off the car will stall out. I did this several times and it always stalled out as I turned the defroster off.

 

No Im not leaving the defroster on always lol./

 

Im not sure if it is a fuel issue but it sure is sucking gas when it runs like this. I had a SES light come on again but I dont have the scanner to pull the code. Its at the shop and it could very well be the same lean condition code.

 

I need help. Does the coils work well then not work so well all at once? or is it a fuel issue and the pump is giving varying fuel pressure while I drive.

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you can jump the ECM to pull codes with a paper clip. take a one and bend it in a U shape, then with the key in the on position, car not running, put each end in the to two right sockets on the connector. the SES light will flash a code 12 3 times, once, then pause, then twice, then it will repeat 2 more times. then it will give you the error codes with the same method. blinking 1,2,maybe three times, then pause, then it will give you the second number, such as 34 or 32. any questions post again.

 

it could be varying fuel pressue, failed pumps that I've dealt with didn't always just fail, they might have been failing. take it for a spin, shut it off and let it run for a while with the tester on. let it run for a bit and see what that gets you.

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I flashed the codes three times over and it just repeats code 12 over and over and over. There is no service engine light on now. Its weird. If you stat up the car let it idle for a minute or so then drive it and get on it. It will be fast as all hell for the first 2-3 times you get a good pull. after that its back to slow rpm climb and surging. Im going to give the fuel pump a go since I have a 255 lying around from an old project. Hopefully it will cure it.

 

If you can shed any light please do. thankyou for all the input so far and keep the information coming.

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I flashed the codes three times over and it just repeats code 12 over and over and over. There is no service engine light on now. Its weird. If you stat up the car let it idle for a minute or so then drive it and get on it. It will be fast as all hell for the first 2-3 times you get a good pull. after that its back to slow rpm climb and surging. Im going to give the fuel pump a go since I have a 255 lying around from an old project. Hopefully it will cure it.

 

If you can shed any light please do. thankyou for all the input so far and keep the information coming.

 

It sounds like your car is running better in open loop operation(where the computer ignores the o2 sensor reading and relies on predetermined inputs). I'll place my bets on a bad o2 sensor(read back over what Jeff M. posted earlier) which is due to the crossover being cracked. If the o2 sensor is bad, it should run a lot better after replacing it, but will eventually be fouled out again since the cracked crossover not only leaks exhaust, but takes in fresh air. When the oxygen sensor reads that extra air, it supplies more gas to the engine, hence the rich/o2 fouling condition.

 

Does the car have the bouncy idle when it's cold or does it have a steadier idle?

 

Also, your fuel pressure specs do seem a little low(I'm pretty sure it's supposed to be over 40psi at idle, but I don't remember the exact specifications).

 

For the rear brake calipers, you need to turn the caliper pistons in to compress them into their bores. Needle nosed pliers will work if you don't want to buy the special tool made to compress them.

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I only have one thing to add as my car once had a plugged cat converter, due partially to the leaking x-over the PO had let go for 10 yrs. Take a look under the car when it's hot and see if the cat converter is glowing. That can make big problems.

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Check the o2 sensor wire for laying melted to the turbo or down pipe area. If not then might be an actual ECM or ground issue, soon as the SES light come on and stays on for longer than 30 seconds and before it starts running good again, pull over and shut off engine/turn key right back to "On" (not Start) and check for codes, better have a code other than the good one/12 or know anyone with a similar ECM to swap as a test? The numbers are 1227727 or 16197128 or 16198620, just make sure to swap chips from yours when testing.

 

Other areas to check are the battery feeds and grounds, those are pretty easy to check, ECM grounds little more work but at some time too if not finding the cause, good to just make sure these are making good contact now and for down the road/less chance later for issues. While it’s not running good, I would for sure stay out of hammering on it, safer this way!!!!...long as you can tell from the idle and other issues when the problem returns. Let us know what you find and we can go from there.

 

Jeff M

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Hey guys no crack in the cross over and cat is not glowing. I dont know how to check the coils.. so.. I put a test light to each plug wire and shot it at nothing to see if it would light up(sparking). from left to right the 6 towers on the coils. I had tower 3&4 only spark once for a period of about 10 seconds then spark again. Not constant blink blink blink like the other 4 wires on the first and last coilpack. I replaced the coil. Now number 3 blinks well and number 4 not so well. Im thinking maybe the ignition module that controls this is shorting? or intermitently pulsing .

 

It helped a bit with the new coil but I would like to make it perfect and not good half the time and worse the other half. I dont like replacing things that dont need to be replaced. and I dont feel like replacing the other two coil packs if they are perfectly fine.

 

Also my car doesnt prime every key turn? I did the fuel pump and after doing it I was really low on fuel I had to prime it like 6 times in a row to fill the lines and start it. I got it running but was really low on fuel and it stalled out. atleast I hope it was from the fuel. It wont prime unless I jerk car around a lil bit. Is there some sortve sensor telling the pump not to prime if there is no fuel in the tank? This is kinda not as important as the coil pack question but is awful helpful. thanks

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pull off the ICM and have it tested a few times at Advance or some other place that will do it for you. You can either remove the 3 coils and then the ICM, or remove the entire thing with the three 13mm bolts around the heat sink that holds it to the block.

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I took the ICM to autozone and checked it and it failed.(I know the people dont know what theya re doing.) I bought a new one. I put it in and the same problem occured. I took it back and got my money back and three new coil packs. Now the car is ok to drive and has plenty of balls off the line but as you get into boost I would guess around 3500-4500 it hits a wall somewhere in there and just doesnt accelerate unless you let off the gas. If i drive like a normal human being and never go WOT this would be fine. But i want to go WOT and have pull al lthe way til redline. Im leaning towards maybe o2 sensor? How can i check it? With the new coil packs in it idles very ncie and starts up great.

 

This problem still isnt cured but I would like to fix it so I can go WOT up the rpm band. It pul;ls like all hell and then doesnt pull. Its not like it just pulls less it just doesnt pull anymore at all. If I drive at halfthrottle it has good respnse and moves good and doesnt hit any walls.

 

Im stuck on this. I would think somthing like either the o2 or fpr. But I just put a new pump in there so I dont think fuel is the problem. I have no SES lights on and this car is driving me nuts.

 

ANyone live around here wanna come see it? I want to fix this damn thing.

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Nice job No1kicker, you guess it!!!!!!! 8) 8) ign coils! Thanks :shock: for the good tip 8)

 

3500 to 4500 rpms lack of power/bog and is it belching rich fuel out the back??? Well, test it then, get someone to drive it and get behind them, or vise-versa, just see if it runs rich when it bogs ok?

 

ANyone live around here wanna come see it? I want to fix this damn thing.

 

Not unless you tell us were you live :roll: Like we all are just dieing to work on another TGP :lol: besides, you are getting good help here, and results so, you just need patience more than anything 8)

 

Jeff M

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I have the same problem. From what I have read, it leads to a bad x-over and a fouled O2 sensor. On my car, neither one have thrown a SES light. Sounds like I am beating a dead cat here because this has been mentioned numerous times in this thread....

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Maybe the O2 is fouled due to the bad coils not firing? I dont have any exhaust leak up front as if i plug the exhaust tips nothing comes out of the engine bay it just pushes the plugs out.

 

Im going to try and just run with the O2 unplugged and see if it changes anything. If it is relying on the O2 for fuel ratio then with it unplugged it should just run pig rich and not hit a wall at 35-3500rpm. right??

 

is it possible mass air is bad since it seems like it hits the wall at WOT during boost.? Im going to take off the whole upper plenum and clean out the MAF and all the other crap IAC and what not and see what I can get. Would cleaning the O2 sensor do anything you think?

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You are not listening :evil: Were do you live if you want free help??? Guys on here know their shit so listen up!!..especially since you are thinking this car has a MAF, it has a MAP and you don't go cleaning it. If you got time to yank the upper intake and can afford ign mod and coils then just replace the damn sensor :lol: simple task, unplugging will be worse then running a fouled one, listen to those here who have worked on and fixed their cars and many other owner's TGPs/TSTEs on here over the last few years, or wear them out and you won't be getting much more help :lol: .

 

You are welcome!

 

I am about done here as are a few others :roll:

 

Jeff M

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Ok caught me in a bad spot. I was getting cars mixed up. Not mass air! Ok Im saying clean the throttlebody/IAC/tps area. If not MAF or VAM what measures the air coming into the motor from the turbo? Im a 2.3 turbo ford guy and we have a vane air meter which measures the airflow and how much air is allowed in inwhich it can tell how much fuel to dump. the MAP is the manifold temp . I had this car on a snapon scanner and said teh MAP sensor was reading 120 degrees. what measures the air coming in on this car"? or is it some type of stand alone? Now im confused. Is the only thing telling this pos anything about the air/fuel ratio the O2 sensor?

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