slipnfall Posted January 20, 2007 Report Share Posted January 20, 2007 Hi Folks, It's nice to find a forum dedicated to this car: it helps when looking for specefic info. Anyways, this is a family car that I'm trying to get straightened out. Let me start from the top: 1)Apparently for a while now, if the fuel gauge drops below 1/4tank, the alternator stops charging the battery(gauge goes low), which results in a dead battery when you stop and go to start back up. If you turn the radio on with the volume all the way down, you can hear a 'thumping' sound coming through the electrical system, especially when stopping or taking off. This is a really strange problem that I'm not too worried about diagnosing right now. 2)Car started bucking and carrying on durring passing and uphill on the interstate, so I was asked to take a look. Afterwards car had a hard time starting, would not idle without help, and stalled frequently. I took a look at the fuel pressure, which was only 10psi or so at *idle*. I changed the fuel pump, filter, sock, and pulsator. The pressure is now up to around 36psi(with FPR vac connected), but this is still apparently low according to spec. Very strange: right after I changed the pump, I primed it a good 3-4times, and the fuel pressure would only rise to 10psi or so again. I cleared the ECM codes afterwards to have a fresh slate. 3)A week later, the car has a very hard time starting: it takes 3-4 cranking cycles to get it to start. Once started it runs just fine. No codes have been thrown. My thoughts are possibly the fuel pump circuit(in which case the oil pressure 'backup' switch takes over to power the pump: but shouldn't this throw a code?), fuel pressure regulator, or crank position sensor. About a year ago my father replaced the coil packs and alternator. The battery is a cheap one and is struggling in this cold weather especially with multiple cranks. Alternator output seems healthy at 14.5Vdc or so. One thing I am waiting to check is for a punctured FPR diafram, but I'm holding out for some warmer days! Thanks for reading folks! Quote Link to comment Share on other sites More sharing options...
dcjredline Posted January 20, 2007 Report Share Posted January 20, 2007 IAC is a common problem on these motors (Specially after a dead battery) may want to check and clean that then relearn idle but only after FP is back to normal. Quote Link to comment Share on other sites More sharing options...
slipnfall Posted January 20, 2007 Author Report Share Posted January 20, 2007 By IAC I presume you mean the intake aux control? The ECM pulses it to allow auxilary air into the intake manifold? I'll do a search, but I'm not sure I see how a dead battery contributes to this solonoid/valve going bad. Thanks for the response BTW! Quote Link to comment Share on other sites More sharing options...
birdman Posted January 20, 2007 Report Share Posted January 20, 2007 IAC = idle air control. after the batt. dies the idle will need to be reset. start the car and put in drive and sit there for like 3-4 min and the idle will be reset. Quote Link to comment Share on other sites More sharing options...
slipnfall Posted January 20, 2007 Author Report Share Posted January 20, 2007 Ok, after I re-read his post I understand what he was getting at. I thought he was implying the IAC was actually bad. Anyways, I did do an idle re-learn after resetting the ECU: followed the procedure on this site actually. I'm going to see what fuel pressure is like here tomorrow and also gently clean the IAC. Have you guys had much luck with sea-foam on these engines? I use it on an import I own, but mainly because the 'IAC' valve is a *huge* pain to get to. Would a faulty FPR cause the lower pressure? I don't think excessive vacuum is causing the pressure to be drawn down. Quote Link to comment Share on other sites More sharing options...
89GP_SE Posted January 20, 2007 Report Share Posted January 20, 2007 ahh god old seafoam, i used it on my 3.1 and it loved it, I loved it even more for smoking up my neiborhood Quote Link to comment Share on other sites More sharing options...
GIANT MOTH Posted January 21, 2007 Report Share Posted January 21, 2007 Hey what is the deal around here? Did we check the alternator for sure? Just because the alternator was changed a year ago doesn't necessarily hold out. And when's the last time you changed a fuel line filter? I bet that things flaking from the cold right now. If all is well definately check the fuel pump from there on in. Well see you back here after you IAC checkup. Quote Link to comment Share on other sites More sharing options...
slipnfall Posted January 21, 2007 Author Report Share Posted January 21, 2007 Again, alternator output was steady at 14-14.5Vdc: I haven't really had it load tested yet, that's a good point. Fuel line filter was changed a week or so before the pump. Quote Link to comment Share on other sites More sharing options...
slipnfall Posted July 28, 2007 Author Report Share Posted July 28, 2007 Ok so this problem is still occuring. I pulled the IAC and gently cleaned it with some mild carb cleaners. Re-installed and relearned the idle. It still takes a good 3-4 cranks to get it to start. I'm *very* seriously considering redoing the fuel pump: my father purchased the pump from Napa I believe, I get the impression the clerk didn't do a good job of cross-referencing it (they had several pumps, but came to a conclusion very quickly, so my father says). ANYWAYS, these random (cold, warm, more frequently at 'cold' start) starting problems came after the pump... so...I don't think I could have caused them from the simple act of replacing it. I was very dilligent about the removal and reinstall. Also there's a funny sound coming from the tank, when the car is turned off... it is a mix between a hissing and the whir of an aftermarket or performance fuel pump(not the case here). If you release the cap it stops. Can someone please point me in the right direction for the GM fuel pump part number? Again this is the 3.1L Cutlass Supreme, '93. I've checked with http://www.gmpartsdirect.com, and they have 2-3 pumps that are described to apply to this car/engine! Thanks for reading! Quote Link to comment Share on other sites More sharing options...
cutlassdude96 Posted July 29, 2007 Report Share Posted July 29, 2007 25163468 Quote Link to comment Share on other sites More sharing options...
GP1138 Posted July 29, 2007 Report Share Posted July 29, 2007 Would a faulty FPR cause the lower pressure? I don't think excessive vacuum is causing the pressure to be drawn down. The FPR is on the fuel rail, it should be readily visible. To check if it is bad, unplug the vacuum line from it, and run it to see if things get better. If not, it's probably not the problem. Quote Link to comment Share on other sites More sharing options...
slipnfall Posted July 29, 2007 Author Report Share Posted July 29, 2007 cutlassdude96: thanks for the part number! I suppose I'll replace the other tank items with GM part numbers also (there's a backflow valve inline if I recall). The pump doesn't include the sock does it? Pibroch(CiH): yep I know if I remove the vacuum I should see the FPR's set-point, around 47psi I believe. I get nothing like that. How does slowly closing the return line test the regulator? I mean, it can only regulate by moving more return fuel, so if you pinch it off, what is that proving? PS - any other discount GM/Olds sites I should check out? GMPartsdirect really socks you on shipping. Thanks kindly! Jamie Quote Link to comment Share on other sites More sharing options...
slipnfall Posted August 4, 2007 Author Report Share Posted August 4, 2007 Hi folks: well I've dropped the tank for a second time. At least it came down really smooth this time: all the bolts were broke free, I knew what had to come off, etc. Anyways, I'm curious to know if the pulsator is functionally neccessary? My father didn't think to get one when he ordered parts form the local dealer... it has a 'new' autozone special on it from the first replacement, but I don't like how it fits. It just doesn't make a good solid seal. Since these hard-start problems came after the pump, I have to wonder if it was the pulsator sucking up air. I do *not* want to drop this tank a 3rd time! What would be the harm in replacing it w/a piece of fuel line (included in the GM pump kit BTW)? The FSM says it is to reduce noise, which I wouldn't be worried about. I took a break for the night: I'll be putting the tank back up tomorrow. If anyone can respond before then I'd appreciate it! PS - for what it's worth, I took a fuel pressure reading at idle before starting: 34psi or so. Kindly, Jamie Quote Link to comment Share on other sites More sharing options...
mfewtrail Posted August 7, 2007 Report Share Posted August 7, 2007 The pulsator is unnecessary(there's a second one on the fuel rail right at the engine anyways). Several people I know have done away with the pulsator in favor of the short piece of rubber fuel line that comes with a new fuel pump kit(AC Delco ones include that) with no issues. Quote Link to comment Share on other sites More sharing options...
slipnfall Posted August 7, 2007 Author Report Share Posted August 7, 2007 Thanks for the reply: a GM pump and omitting the pulsator seemed to do the trick. The car has fired up on the first crank every time now since Saturday, so it is looking good! Cold start fuel pressure was still low, around 37psi, but built to around 40-ish after a minute or so of running. Thanks for all the help folks! Quote Link to comment Share on other sites More sharing options...
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