55trucker Posted April 19, 2014 Report Share Posted April 19, 2014 Bridge the fuel pump relay to engage the pump, with your pressure gauge attached to the rail read the pressure, if low then pinch off the return hose back to the tank, note the pressure reading on the gauge, if it changes by increasing then you have a probable FPR failure. If it does not change then start looking at the pump or a restriction in the pressure side before the rail. Quote Link to comment Share on other sites More sharing options...
PTAaron Posted April 19, 2014 Author Report Share Posted April 19, 2014 topping off at 15, i would expect the FPR is the issue. i can't remember if there is anywhere to do so, but are there any rubber sections to pinch on the return line to deadhead the pump? Unfortunately the lines are all hard plastic if they aren't metal as far as I can see. We had the same thought but that idea got shot down quick. Apparently there is a part of harness right at the top of the pump that corrodes and can cause low voltage, etc. Was too small of wiring gauge from the factory Yeah, that is something we were looking into - we were going to try to test voltage at the pump but it looks like you can't get to the wires without dropping the tank... Bridge the fuel pump relay to engage the pump, with your pressure gauge attached to the rail read the pressure, if low then pinch off the return hose back to the tank, note the pressure reading on the gauge, if it changes by increasing then you have a probable FPR failure. If it does not change then start looking at the pump or a restriction in the pressure side before the rail. Can't seem to find a place where we can pinch the return line - it seems to be hard plastic from what we could see... is there a soft rubber area where we could pinch? Quote Link to comment Share on other sites More sharing options...
PTAaron Posted April 19, 2014 Author Report Share Posted April 19, 2014 I stand corrected - the hoses are softer now than they were when it was 35 degrees out this morning and we started working on this... Pinching the return hose does absolutely zero to the fuel pressure reading. So the pump is only putting out 15psi? We're trying to probe the wires at the pump to check voltage drop to see if running a heavier wire may solve the issue... failing that its back up to the auto parts store to buy that damn pump. Unless there is something else it could be? Quote Link to comment Share on other sites More sharing options...
Schurkey Posted April 19, 2014 Report Share Posted April 19, 2014 You're installing a fuel filter anyway...right? After you've removed the filter, connect your pressure gauge to the pipe coming out of the fuel tank. Jump the relay, or put power to the relay bypass wire--whichever activates the fuel pump. You'll have full pressure at the fuel tube, and the regulator is out of the circuit. Toughest part will be figuring out how to connect the gauge to the fuel tube. Quote Link to comment Share on other sites More sharing options...
PTAaron Posted April 19, 2014 Author Report Share Posted April 19, 2014 You're installing a fuel filter anyway...right? After you've removed the filter, connect your pressure gauge to the pipe coming out of the fuel tank. Jump the relay, or put power to the relay bypass wire--whichever activates the fuel pump. You'll have full pressure at the fuel tube, and the regulator is out of the circuit. Toughest part will be figuring out how to connect the gauge to the fuel tube. We had that thought, but weren't sure we could get a good seal to test pressure. We did however decide that the 15 gallons of gas in the tank needed to come out if we had to proceed with a pump replacement, so we have a hose tucked into the fuel tube and going into a bucket - where it is barely coming out with significant air bubbles. We checked voltage at the pump wiring harness and with the engine running it was 13.8... this is all making us believe the pump is not putting out enough pressure for some reason. Quote Link to comment Share on other sites More sharing options...
RobertISaar Posted April 19, 2014 Report Share Posted April 19, 2014 neat things for the future/possibly now: pumps don't create pressure, they create flow. restriction to flow is more or less the exact definition of pressure for automotive usage. the pump isn't creating enough flow to build up the pressure required for the fuel injection system to operate properly, that seems to be the case here. clamping off the return line SHOULD have run the pump up to ~70PSI or so, that is about where the stockers can't actually push any more fuel into the lines and will "stall" or otherwise just not work cirrectly. Quote Link to comment Share on other sites More sharing options...
Schurkey Posted April 19, 2014 Report Share Posted April 19, 2014 (edited) we have a hose tucked into the fuel tube and going into a bucket - where it is barely coming out with significant air bubbles. I did that. Used the fuel pump to empty the fuel tank before removal of the tank. Like you, I got a fairly disappointing stream of fuel from the dying pump. Don't forget that you could have a failed (leaking) fuel pulse damper. Not likely, but possible. Some vehicles use a short length of SPECIAL fuel hose to connect the pump to the tube on the sending unit assembly. This hose has to be rated for immersion in gasoline, ordinary fuel hose isn't. Or a plugged strainer on the bottom of the pump. We checked voltage at the pump wiring harness and with the engine running it was 13.8... this is all making us believe the pump is not putting out enough pressure for some reason. Better to check current flow in addition to the voltage. Not many do-it-yourselfers are equipped for current measurements. A current probe connected to an oscilloscope is friggin' MAGICAL for diagnosing failed fuel pumps...but who has the current probe, let alone the 'scope? When you pull the pump out, be sure to check the in-tank wire harness. They're almost always corroded, if not outright melted at the plastic connector bodies. The solution is to inspect the connectors built-into the sending unit body, and if they're in good condition, buy a new harness from your favorite parts store. The new harness was longer than the old one. Not a problem. You MUST MUST MUST clean all the rust and dirt particles out of the tank. Particle contamination that gets past the filter sock on the pump is the number-one cause of early fuel pump failure. Edited April 19, 2014 by Schurkey Quote Link to comment Share on other sites More sharing options...
Nas Escobar Posted April 19, 2014 Report Share Posted April 19, 2014 Would love to do that, but there are 2 big problems: I don't have $300-600 to spend on something I will only use once, and I wouldn't know what I'm looking at unless it is spelled out in really simple terms. We're to the point where if it is going to cost more than $100 to get the car running again, it is just going to be donated to charity and I will buy something made in this decade. I know this post is a month old, but you should know that you don't have to spend a crazy amount of money on a scan tool. If you luck out on diagnosing it and getting it running once and for all, then discard this, but if it still acts up you just have to man up and get some sort of scannning tool. Do you have a laptop? Because all you need is a laptop running windows and a $60 ALDL cable that connects to your laptop via USB. Then you download Tunerpro and you're golden. You can see the data stream from you car's OBD computer. It's pretty simple to understand it, there's a dashboard feature where you can get readouts. Once you see it, it's pretty understandable. Here's a link. http://www.ebay.com/itm/GM-OBD1-Scanner-Cable-Software-USB-to-12-pin-ALDL-direct-GM-OBDI-/111245393571?hash=item19e6bdfea3&item=111245393571&pt=Motors_Automotive_Tools&vxp=mtr Quote Link to comment Share on other sites More sharing options...
RobertISaar Posted April 19, 2014 Report Share Posted April 19, 2014 i should really make rental ALDL cables for situations like this..... Quote Link to comment Share on other sites More sharing options...
PTAaron Posted April 19, 2014 Author Report Share Posted April 19, 2014 Update - right now we're refilling the tank with fuel... Dropping the tank was physically difficult due to the rusted in place bolts and stuck on "quick disconnects" - otherwise uneventful. Pump wires looked OK, but the new pump came with a wiring harness so we swapped it in. Filter bag looked "OK", but we put on a new one anyway. New pump had a hose included for us to use and instructions said to remove the pulse dampener - so we did. Once we get some fuel in place, we'll see what it looks like! Thanks everyone so far for the input. THanks for the tip Nas! Quote Link to comment Share on other sites More sharing options...
PTAaron Posted April 20, 2014 Author Report Share Posted April 20, 2014 Just got done test driving... Aside from rusty brakes, the car drives just like it did before the head gasket problem! I am grateful to all of you for your input and help tracking the problems down. I really didn't want this car to defeat me - and it didn't!! Quote Link to comment Share on other sites More sharing options...
PTAaron Posted April 20, 2014 Author Report Share Posted April 20, 2014 ...and we came home from dinner, opened the garage door, and there is a puddle under the Cutlass! Right under the fuel filter... but it is brake fluid! Pushing the brake pedal creates a nice fountain-like effect under the car from a pinhole leak just after a union in one of the lines. Apparently it got jarred around when we were working around the fuel filter. Tomorrow morning we'll be replacing that - and THEN the car should be good to go! Quote Link to comment Share on other sites More sharing options...
Schurkey Posted April 20, 2014 Report Share Posted April 20, 2014 i should really make rental ALDL cables for situations like this..... No reason. Anyone with commitment to fixing their car can buy their own. Anyone without commitment won't know how to use it anyway. Quote Link to comment Share on other sites More sharing options...
Night Fury Posted April 20, 2014 Report Share Posted April 20, 2014 YAY! Glad to hear you had some success! Quote Link to comment Share on other sites More sharing options...
Nas Escobar Posted April 20, 2014 Report Share Posted April 20, 2014 ...and we came home from dinner, opened the garage door, and there is a puddle under the Cutlass! Right under the fuel filter... but it is brake fluid! Pushing the brake pedal creates a nice fountain-like effect under the car from a pinhole leak just after a union in one of the lines. Apparently it got jarred around when we were working around the fuel filter. Tomorrow morning we'll be replacing that - and THEN the car should be good to go! Glad you finally got the car running! No reason. Anyone with commitment to fixing their car can buy their own. Anyone without commitment won't know how to use it anyway. Of course telling people to buy scan tools doesn't help the situation either considering the fact that there's loads of scan tools out there and they all claim to work on OBD1 and 2 yet only a handful of them do. The fact that most don't know there's a cable that can connect to the most common electrronic in today's world also feeds into the misconception that you need to buy a rectable object that connects to your car and retrives codes. In fact, I want to get an OBD2 USB cable so I can mess around with my Camaro. I'm almost tempted to make a how to for this forum for that ALDL cable. Quote Link to comment Share on other sites More sharing options...
PTAaron Posted April 20, 2014 Author Report Share Posted April 20, 2014 YAY! Glad to hear you had some success! Thanks! I really didn't want to car to win in this battle... I need a newer car for a variety of reasons, I just didn't want to be forced into it. This way I can take my time - and maybe even make $10-20 selling a running Cutlass with a swiss cheese body at some point Glad you finally got the car running! Of course telling people to buy scan tools doesn't help the situation either considering the fact that there's loads of scan tools out there and they all claim to work on OBD1 and 2 yet only a handful of them do. The fact that most don't know there's a cable that can connect to the most common electrronic in today's world also feeds into the misconception that you need to buy a rectable object that connects to your car and retrives codes. In fact, I want to get an OBD2 USB cable so I can mess around with my Camaro. I'm almost tempted to make a how to for this forum for that ALDL cable. Thank you! It is a huge relief. A how-to would be great. That is something I would consider messing with just to simply learn about how things work. Quote Link to comment Share on other sites More sharing options...
Nas Escobar Posted April 20, 2014 Report Share Posted April 20, 2014 Thanks! I really didn't want to car to win in this battle... I need a newer car for a variety of reasons, I just didn't want to be forced into it. This way I can take my time - and maybe even make $10-20 selling a running Cutlass with a swiss cheese body at some point Thank you! It is a huge relief. A how-to would be great. That is something I would consider messing with just to simply learn about how things work. You could keep the car as a spare. It never hurts to have 2 cars. I'll get on that when I get my laptop working. Sent from my HTC using Tapatalk. Quote Link to comment Share on other sites More sharing options...
PTAaron Posted April 21, 2014 Author Report Share Posted April 21, 2014 You could keep the car as a spare. It never hurts to have 2 cars. I'll get on that when I get my laptop working. Sent from my HTC using Tapatalk. At one point we had 5 cars - was nice to have spares, but only having a 2 car garage stinks in the winter when the "driver" cars have to stay out in the snow Down to 3 at the moment now that I sold off the XR4Ti, and had to lose the Contour SVT after it cracked a piston skirt when a shop left me without oil after some repair work and I didn't catch it for a few hundred miles. Quote Link to comment Share on other sites More sharing options...
PTAaron Posted April 24, 2014 Author Report Share Posted April 24, 2014 About 200 miles on the car so far this week - running like a champ. Monday was flawless aside from a noisier engine due to the exhaust leaks caused by removing the manifolds and putting them back on - there were 1 broken studs on cylinder 1 and 2 studs broken on other cylinders - we tried to extract the broken pieces but succeeded only in breaking the extractors. I'm OK with a little noise... Tuesday I got a check engine light on the ride home from work. Wednesday check engine light half the ride to work, half the ride home. Today - check engine light on the way to work... hoping it comes on on the way home so I can stop off at Autozone and have them pull the codes for me. Gas mileage seems to be a bit better than it was prior to the headgasket replacement - we'll know for sure tomorrow morning for sure... was getting about 22mpg with my non-expressway driving to/from work. Quote Link to comment Share on other sites More sharing options...
Nas Escobar Posted April 26, 2014 Report Share Posted April 26, 2014 Since your car is a 94, Auto Zone won't be able to pull the codes. You would have to get the ALDL cable I mentioned earlier. Quote Link to comment Share on other sites More sharing options...
19Cutlass94 Posted April 27, 2014 Report Share Posted April 27, 2014 Ive pulled codes from 1994-1995 cars with just regular scanners before. After all, it is only OBD1 Quote Link to comment Share on other sites More sharing options...
Nas Escobar Posted April 27, 2014 Report Share Posted April 27, 2014 Aren't the entrances different though? Quote Link to comment Share on other sites More sharing options...
nitehawkjcb Posted April 28, 2014 Report Share Posted April 28, 2014 I know some OBD1 cars have a connector that you jump and the CEL flashes your codes. Extracting broken bolts and studs suck, that's for sure. Glad it's running like it should... Hopefully the CEL is something small. It should store the code, regardless of the light being on or not. Quote Link to comment Share on other sites More sharing options...
19Cutlass94 Posted April 28, 2014 Report Share Posted April 28, 2014 Nope. It's all the same all OBD1 connectors are the same. Same with OBD2. Unless you have a lotus or some oddball foreign car. Sent from my iPhone Quote Link to comment Share on other sites More sharing options...
Schurkey Posted April 28, 2014 Report Share Posted April 28, 2014 Nope. It's all the same all OBD1 connectors are the same. Same with OBD2. Unless you have a lotus or some oddball foreign car. Sent from my iPhone If what you mean is all the pre-OBD-2 W-bodies have the same OBD-1 connector, you might be correct. No promises that they're all wired the same, though. My scan tool came with two OBD-1 adapters for GM, at least one for Ford, at least one for Chrysler, and another for Jeep. I think every Jap brand has a unique design. There's plenty of different designs for OBD-1 in general, which is one reason it was standardized for OBD-2. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.