RobertISaar Posted March 30, 2014 Report Share Posted March 30, 2014 yes, timing is HIGHLY dependant upon an accurate MAP signal, as is fuel delivery. Quote Link to comment Share on other sites More sharing options...
Imp558 Posted March 30, 2014 Report Share Posted March 30, 2014 Pardon my ignorance, not a 3100 guy but this engine has no MAF? A speed density engine relies on IAT to tell the PCM how dense the air is, and a MAP to tell it how much pressure or vacuum is in the manifold so if either of them is off the PCM has a very wrong idea of the airflow and is limited. You found the gray wire on the MAP is a 5V reference, the signal should be light green and the 3rd wire is the low ref, typically black or violet. If the low ref wire is open and not a good ground the MAP will give a funny reading too. You might try (ignition on) testing voltage between the 5V ref wire(Gray) and low ref (Black or Violet) and see if you have close to 5Volts there, in the real world it'll be close like 4.7-4.9Volts. Also the IAT should be a tan wire and a low reference, that low ref should be close to ground or read the same close to 5V when read from the MAP gray 5V wire and it. Honestly when I do a swap or am honeymooning a new car I always replace the IAT and also the CTS, they're just cheap insurance. Quote Link to comment Share on other sites More sharing options...
Schurkey Posted March 30, 2014 Report Share Posted March 30, 2014 Honestly when I do a swap or am honeymooning a new car "Honeymooning" a car. Wonderful. I never thought to call it that, but I know exactly what you mean. Quote Link to comment Share on other sites More sharing options...
Imp558 Posted March 30, 2014 Report Share Posted March 30, 2014 Till death due us part, and where I'm from their life expectancy is only 100K miles before the road salt eats them. Quote Link to comment Share on other sites More sharing options...
PTAaron Posted March 30, 2014 Author Report Share Posted March 30, 2014 (edited) Honestly when I do a swap or am honeymooning a new car I always replace the IAT and also the CTS, they're just cheap insurance. Â I am following what you are saying, but you lost me on the last sentence: CTS=coolant temp sensor IAT= Â What is the IAT? Is that the little sensor on air intake rubber hose? If so - there is a chance that got contaminated with some of the sludge from the headgasket blowing. Edited March 30, 2014 by PTAaron Quote Link to comment Share on other sites More sharing options...
Imp558 Posted March 30, 2014 Report Share Posted March 30, 2014 Intake Air Temp and yes, its the little guy in the airstream. 2 Pin gray plug. Quote Link to comment Share on other sites More sharing options...
Garrett Powered Posted March 31, 2014 Report Share Posted March 31, 2014 Â Â Â timing is non-adjustable, the PCM and ICM takes care of all of that. if actual timing were different than commanded timing...... then something has gone seriously wrong. Â still trying to figure out what is meant by this.. you mean the timing tables aren't tuneable? Quote Link to comment Share on other sites More sharing options...
RobertISaar Posted March 31, 2014 Report Share Posted March 31, 2014 for the average person, they're not. the average person usually doesn't have an ALDL cable, let alone calibration and flashing software. Quote Link to comment Share on other sites More sharing options...
PTAaron Posted April 1, 2014 Author Report Share Posted April 1, 2014 Alrighty guys... drove the car around a good part of the day Sunday, keeping the throttle to 50-75% max and not having any major problems. Stopped off at Walmart to pick up some food and trans fluid for a fluid change on my wife's Saturn - came back out the the Cutlass and couldn't get it to start. It would fire, sputter, then die. The fuel level was down at 1/8th tank, so I was planning to hit the gas station as soon as we left Walmart - but I ended up walking over to the gas station to get 2 gallons, added that to the car and still no luck. Called AAA and got picked up by a flatbed - nothing says "class" like having your car flatbedded out of the Walmart parking lot, let me tell you! Got home and gave it another try - after cranking it for about 30 seconds it finally started and ran JUST FINE. This morning I drove it to the gas station to fill it up, then to the gym... ran fine as long as I didn't hit the throttle too hard. After working out it started roughly, and ran kind of rough halfway home then smoothed out again. Â I'm wondering if I have a fuel delivery issue maybe?? Will check fuel pressure this week... I'm not sure where I'm going to have to stop replacing things... spent another $150 last weekend on 2 sensors, oil, and a new battery - can't keep throwing money at this thing! Would be different if it didn't have a massive rust hole in the trunk! Quote Link to comment Share on other sites More sharing options...
Imp558 Posted April 1, 2014 Report Share Posted April 1, 2014 Mine was doing that crap and it was fuel pump wiring Quote Link to comment Share on other sites More sharing options...
PTAaron Posted April 1, 2014 Author Report Share Posted April 1, 2014 Mine was doing that crap and it was fuel pump wiring  Hmm... How did you track that down? Quote Link to comment Share on other sites More sharing options...
Imp558 Posted April 1, 2014 Report Share Posted April 1, 2014 It's a known issue, the wire to the fuel pump is a bit too small to begin with, then once it ages it's insufficient. Next time it happens take a hunk of wire and bypass the FP relay and see if it helps. I replaced my relay with a better aftermarket one to get bye and when I do my trunk mount battery I'll be re-locating my relay to the trunk so the pump power wire is only a few feet long. On the relay it should be orange to gray to jump it. Do NOT jump the Green/white to anything! Quote Link to comment Share on other sites More sharing options...
PTAaron Posted April 1, 2014 Author Report Share Posted April 1, 2014 (edited) It's a known issue, the wire to the fuel pump is a bit too small to begin with, then once it ages it's insufficient. Next time it happens take a hunk of wire and bypass the FP relay and see if it helps. I replaced my relay with a better aftermarket one to get bye and when I do my trunk mount battery I'll be re-locating my relay to the trunk so the pump power wire is only a few feet long. On the relay it should be orange to gray to jump it. Do NOT jump the Green/white to anything! Thanks, I will do some research on that - sounds like a fairly easy fix once I can ID the right wires. I have noticed over the time I've owned the car that I hear the fuel pump sometimes when i turn the key to the run position and other time I don't... and sometimes I get a popping through the radio/speakers in the "run" position with the engine off. Wonder if that is related. Â Oddly enough, I have a trunk mount kit sitting in my garage from a different car - any advantage to doing it on a w-body? I did it with my XR4Ti because they brilliantly positioned the battery directly over the turbo. Edited April 1, 2014 by PTAaron Quote Link to comment Share on other sites More sharing options...
nitehawkjcb Posted April 1, 2014 Report Share Posted April 1, 2014 Thanks, I will do some research on that - sounds like a fairly easy fix once I can ID the right wires.I have noticed over the time I've owned the car that I hear the fuel pump sometimes when i turn the key to the run position and other time I don't... and sometimes I get a popping through the radio/speakers in the "run" position with the engine off. Wonder if that is related. Â Oddly enough, I have a trunk mount kit sitting in my garage from a different car - any advantage to doing it on a w-body? I did it with my XR4Ti because they brilliantly positioned the battery directly over the turbo. Â I had an issue with the wiring in the fuel tank also, so that could be your issue... The only advantage I know of is being able to run a fenderwell intake (but this is on 5th gen Montes). Â And you had an XR4Ti also? Cool. Hope it ran better than mine did lol Quote Link to comment Share on other sites More sharing options...
Imp558 Posted April 1, 2014 Report Share Posted April 1, 2014 Hell yeah, if you trunk mount you can sever the green/white wire from the relay, and tie it to the gray wire and then use the gray wire to trigger a relay in the trunk. Just check at the oil pressure plug and make sure that gray wire doesn't gi to it, I can't remember. Quote Link to comment Share on other sites More sharing options...
PTAaron Posted April 17, 2014 Author Report Share Posted April 17, 2014 I had an issue with the wiring in the fuel tank also, so that could be your issue... The only advantage I know of is being able to run a fenderwell intake (but this is on 5th gen Montes). And you had an XR4Ti also? Cool. Hope it ran better than mine did lol I will definitely check that - I've been out of town for a while so the car has been sitting in the driveway... Just seems really strange that it would suddenly become a problem while I was fixing the engine. Yeah - I actually had 4 XR4Tis - they run great if if you do a few tweaks on them My last one had a LOT of tweaks, so it was really fun.  Hell yeah, if you trunk mount you can sever the green/white wire from the relay, and tie it to the gray wire and then use the gray wire to trigger a relay in the trunk. Just check at the oil pressure plug and make sure that gray wire doesn't gi to it, I can't remember.  Good info, thanks! Quote Link to comment Share on other sites More sharing options...
PTAaron Posted April 17, 2014 Author Report Share Posted April 17, 2014 This morning I finally had a chance to get back to the car - been out of town for a while... Â Father in-law loaned me a fuel pressure gauge that attaches to the schrader valve on the fuel rail... but it was reading no fuel pressure at idle. Seems unlikely to be the case since it was idling well Is that valve an accurate indication of fuel pressure? Â I also checked each coil and they all had spark while the engine was running. My concern was maybe one of the fuel injector harness wires came loose while re-installing the fuel rail, not sure if there is an easy way to figure that out without having to pull the upper off again? Â I guess my confusion here comes from the fact that the fuel pump worked just fine before the car overheated, and nothing beyond the engine compartment has changed since that time... so why would it fail all of a sudden? Seems like the issue MUST be located in the engine compartment, no? Â I will double check the fuses since I had to pull the fuel pump fuse when I did the compression testing... maybe somehow it didn't get seated right? Quote Link to comment Share on other sites More sharing options...
Schurkey Posted April 17, 2014 Report Share Posted April 17, 2014 it was reading no fuel pressure at idle. Seems unlikely to be the case since it was idling well Is that valve an accurate indication of fuel pressure? Nope. Something isn't right. Wrong size/style fitting on the gauge to press the Schrader fitting valve core? Quote Link to comment Share on other sites More sharing options...
Galaxie500XL Posted April 17, 2014 Report Share Posted April 17, 2014 Possible fuel pressure regulator problem, or no vacuum to the regulator? Quote Link to comment Share on other sites More sharing options...
PTAaron Posted April 18, 2014 Author Report Share Posted April 18, 2014 Nope. Something isn't right. Wrong size/style fitting on the gauge to press the Schrader fitting valve core? I think maybe I didn't let it idle long enough - the hose on this gauge is about 8 feet long! I adjusted the fitting when I got home from work to make sure it was pushing the plunger on the valve and let it sit at idle longer... now it is reading around 15psi at idle. From what I've bee seeing online - this is quite low. I didn't feel like getting stranded down the street in the dark so I didn't drive it to see if it was different under load. Â Possible fuel pressure regulator problem, or no vacuum to the regulator? Vacuum line to the regulator is attached and drawing vacuum. If I disconnect it while the engine is running there is a nice vac on the hose that I have to cover with my thumb to keep the car running smoothly. Â I THINK I've located the "fuel pump prime" wire near the drivers side strut tower - the Haynes manual says I can put 12V to that and it should make the pump run, so I'll give that a try to verify my pump is working properly. Â When we were doing the head gasket we left the fuel rail connected to the fuel lines and kind of flipped it off to the side out of the way - I'm wondering if we could have damaged SOMETHING that would make the pressure drop? Not quite sure how to test the FPR other than trying to apply more vacuum to it with a pump? Quote Link to comment Share on other sites More sharing options...
Night Fury Posted April 18, 2014 Report Share Posted April 18, 2014 That's all I ever do with the rail is to set it aside. Missing and running crappy is very indicative of a fuel pressure problem though. Maybe try a fuel filter for a cheap possible solution before digging further with the fuel pump? Quote Link to comment Share on other sites More sharing options...
PTAaron Posted April 19, 2014 Author Report Share Posted April 19, 2014 Thanks for the thought. I did pick up a fuel filter - I had thought about it when we were doing the other work just because I thought it would need one soon anyway, but never got one. Â Â After trying to jumper what I think is the fuel pump prime wire I got zero sound from the pump. I did get sparks from the wire as I connected it to 12V power, so I know it was doing something. I checked resistance and there was resistance so it is completing a circuit somewhere. Assuming I have the right wire (posting a pic to confirm) - this means the pump DID just coincidentally die while we were doing the head gasket. WHAT THE HELL? I never have that kind of luck when it is GOOD luck. I will do more testing tomorrow when my father in-law comes by - we'll try jumpering at the relay to see if that kicks the pump on before I go out and buy a new pump. Â This is THE last thing I will be replacing on the car - if it doesn't run someone will get a really cheap can that just needs a few more parts Quote Link to comment Share on other sites More sharing options...
PTAaron Posted April 19, 2014 Author Report Share Posted April 19, 2014 Okay... more testing today - jumpered across the fuel pump relay and the pump runs. It only pumps up to 15 PSI though. Started the car and watched the pressure gauge - it stays steady at 15 psi. Used a small vacuum pump to apply more vac to the FPR - still stays at 15psi. Â In the process of replacing the fuel filter right now - with as hard as it has been to get this damn thing off it almost seems like replacing the pump would have been easier. Right now we just can't get the quick connect to go back together with the spacer/o-ring in place. Taking a break to thaw out before going out and swearing at it some more. Â Clogged filter could cause low pressure - we'll see if that fixes it... FPR maybe? Low voltage to the pump maybe? Quote Link to comment Share on other sites More sharing options...
RobertISaar Posted April 19, 2014 Report Share Posted April 19, 2014 topping off at 15, i would expect the FPR is the issue. Â 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? Quote Link to comment Share on other sites More sharing options...
Night Fury Posted April 19, 2014 Report Share Posted April 19, 2014 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 Quote Link to comment Share on other sites More sharing options...
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