FXd_up Posted May 23, 2011 Report Share Posted May 23, 2011 Hello, and thanks ahead of time for taking the time to read this post. I'm new to the site, obviously, and the reason that I'm here is because I need help with a car that I seemed to inherit. I'm the new owner of a 91' Cutlass Supreme with a 3.1 and just over 80k miles on it. It's been garaged mainly, but this was my grandmother's old car and I've heard that she tended to have a lead foot when she drove it. On to the good stuff....this car is now stuck in my culdesac and does not start. It will turn over just fine and stumbles sometimes as if it's trying to start. If I open the throttle up while turning it over it backfires out of the intake. The problem started when my friend (who was using the car at the time) started hearing backfires out of the intake (or some sort of thumping sound from under the hood) and it died at a stop light. We were able to start it a couple of times, however it ran VERY poorly and when ANY sort of throttle was added it would die. The only thing I have tried so far is replacing the MAP sensor, however it would do the same thing. I jumped the pins on the obd port to display a code, however the only thing that happens is the check engine light keeps blinking repeatedly at a constant rate. Any help is much appreciated....I won't bring this to a mechanic however I am currently enrolled in ASE mechanic's school and have a lot of experience with working on cars and trucks. Thanks! Quote Link to comment Share on other sites More sharing options...
Pabz Posted May 23, 2011 Report Share Posted May 23, 2011 Sounds like it could be the ignition coils and/or ignition control module. Testwith somefroma junkyard Quote Link to comment Share on other sites More sharing options...
joecutlass Posted May 23, 2011 Report Share Posted May 23, 2011 Ohm test the injectors. I had a similar problem with my 89 cutlass sl. Quote Link to comment Share on other sites More sharing options...
19Cutlass94 Posted May 23, 2011 Report Share Posted May 23, 2011 First two things you need, are fuel and spark. makre sure you have both of those, then go from there. Quote Link to comment Share on other sites More sharing options...
Decatur 31 Posted May 23, 2011 Report Share Posted May 23, 2011 Does that engine have a timing belt or chain? If it has a belt it could have jumped a tooth. I have had engines that would run even when they were one tooth off although they ran poorly and would back fire through the intake. They weren't fuel injected but just something to file away for the future. Good luck. Jerry Quote Link to comment Share on other sites More sharing options...
19Cutlass94 Posted May 23, 2011 Report Share Posted May 23, 2011 (edited) It has a timing chain. Normally this happens when timing is off. Which could be timing chain or cam senor(s). But could be caused from leaking injectors, which cause fuel to be in the cylinder when the intake valve opens or ingition crossfire. But its always good to check your basics ( like fuel and spark that I mentioned ealier ) Because theres several issues that could cause this. Edited May 23, 2011 by 19Cutlass94 Quote Link to comment Share on other sites More sharing options...
RobertISaar Posted May 23, 2011 Report Share Posted May 23, 2011 constant blink rate with the ALDL pins shorted is a problem. if you can't get even code 12 to pop up, then either your ECM or PROM is junk. either of those going out can cause all kinds of weird crap to happen. Quote Link to comment Share on other sites More sharing options...
FXd_up Posted May 23, 2011 Author Report Share Posted May 23, 2011 constant blink rate with the ALDL pins shorted is a problem. if you can't get even code 12 to pop up, then either your ECM or PROM is junk. either of those going out can cause all kinds of weird crap to happen. That's not encouraging at all....spark and fuel is what I'm going with so far and I'm going to start testing those....though a fried ECU would be no fun. I should also mention that the blinking from the ALDL is a rapid blinking rate, maybe that can tell you guys something. Quote Link to comment Share on other sites More sharing options...
RobertISaar Posted May 23, 2011 Report Share Posted May 23, 2011 are you trying this with the engine running or not? to do the blinkout test, the engine MUST be off, otherwise, field service mode is enabled and the blink rate and on/off time are actually representative of the O2 sensor readings. when doing the blinkout, a cooling fan should kick on as well. Quote Link to comment Share on other sites More sharing options...
FXd_up Posted May 23, 2011 Author Report Share Posted May 23, 2011 yes, the engine was off when i did the blinkout text. The cooling fan did kick on. Quote Link to comment Share on other sites More sharing options...
GnatGoSplat Posted May 25, 2011 Report Share Posted May 25, 2011 Fried ECM is actually quite easy to replace. Every time I had a fuel pump go bad, I also got the backfire from the intake. There is a loose small gauge wire by the battery with a gray connector on the end, it's the fuel pump prime. Touch that to the positive jump start terminal and see if the pump runs. If it doesn't run, the pump is bad. If it runs, check fuel pressure. If you don't have enough pressure, try replacing the fuel filter and check again. If still no pressure, replace pump. Quote Link to comment Share on other sites More sharing options...
EviLette Posted May 29, 2011 Report Share Posted May 29, 2011 Fried ECM is actually quite easy to replace.Every time I had a fuel pump go bad, I also got the backfire from the intake. There is a loose small gauge wire by the battery with a gray connector on the end, it's the fuel pump prime. Touch that to the positive jump start terminal and see if the pump runs. If it doesn't run, the pump is bad. If it runs, check fuel pressure. If you don't have enough pressure, try replacing the fuel filter and check again. If still no pressure, replace pump. What he said. I have a 92 Grand Prix, but it's the same 3.1 engine you are dealing with. I have had problems with fuel pumps going out but not totally dying. I would get fuel pressure, but not enough volume of it to actually make the car run. She would sputter and spit and die randomly, wouldn't want to start, and when accelerating from a stop would die. The ECM and coil packs are notorious for going out on these cars, I think particularly on the older 3.1 engines. I actually keep spare coil packs in my trunk just in case. When they start acting up, they will misfire in a number of ways (by not firing right, or by arcing.) Sometimes it will seem heat related, and sound somewhat like a backfire under the hood. The car will also generally have a noticeable miss in this case... not always, but generally. So yeah, what the guys are saying above is correct, all great ideas. Check for fuel pressure. Check for spark. If you good fuel pressure, test the injectors to make sure they are all above 12ohms. If there's a spark issue, check the ignition system items. Three coilpacks, you can pick them up pretty cheap at junkyards - I look for the ones that are actually numbered - those are original (or Delco OEM) and seem to function better than aftermarket. If those are good, ECM might be hiccuping. The problem with testing them at a parts store though is that they can test and say they are good when they are arcing ONLY when they get warm, so they wouldn't necessarily pick up on the issue. Seen it before. Quote Link to comment Share on other sites More sharing options...
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