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I have been having a intermediate issue with my engine surging, not just at idle but even when cruising, I will be sitting at idle and the car will jump 400 or so rpm.( sometimes surge up and down) I will be crusing along at 2200 rpm and the same thing will happen. When I come to a stop the idle will be way up, sometimes it will fluctuate up and down until I take off but the same happens when I get to the speed limit and stay at speed. Some mornings When it is warming up I will here it drop and then surge up to 1500 or better and idle there. Either way the fix is to just shut it off and restart. I never know when this happens, I will go for a day or better and then it will start acting up again. Sometimes it will come back right after I restart, no rhyme or reason. I have owned the car for about a year and have redone the vac. lines, complete ignition, Cleaned and or replaced sensors, the fuel pump and regulator were new when I bought it. I posted here because I have a 305 TPI. The car had 70,000 when I bought it so it has not been driven alot over the years and was thinking it might be injector related. https://www.thirdgen.org/forums/imag...lies/hmmmm.gif
Thanks Guys
I have no idea, but I would look at the iac. google tpi iac reset and/or surge. Most likely nothing to do with your issue, but my thought on it.. good luck..
I have no idea, but I would look at the iac. google tpi iac reset and/or surge. Most likely nothing to do with your issue, but my thought on it.. good luck..
That is one of the sensors I cleaned. It looks like some prior to me has replaced it, the clip was broke and it looked fairly new. I will try a goggle search.
O.K. I did a google search and for the most part they all led back to here with multiple unfinished threads on this problem. The other sites really did not give much info on problems. This morning when I left for work, took off down the road and when I hit 30 mph I let off the gas, The engine jumped and took off again 2 times before it came down. I was like I stepped on the gas real fast and let off. It idled @ around 1200 in drive the rest of the way. Just went to the bank and the car ran perfect. No surges, 700 or so in drive.
Any Ideas welcome...I am stumped!
Thanks, I will give this a try over the weekend and let you know how I make out.
I did the IAC reset and it somewhat fixed the issue. 1st it made the engine run much better overall, soother and faster starts, especially when cold. It got rid of the RPM surge. But at some point the idle will fluctuate a couple hundred rpm when sitting in drive at a light, and end up at some point that the idle ends up running around 1000 in drive. If I turn the engine off and restart the car runs perfect, no matter how far I go or how many times I restart. Once it fully cools(or the next day) it goes through this cycle again but at least the last 3 days it has been consistent.
I did not do the TPS part. I could not get a jumper wire(or a paper clip) into that rubber seal of the plug. I did not want to force the paper clip as I was afraid it would damage the waterproof seal. I will see if I can get a tester tool listed in the instructions.
Problem is back. I think the IAC reset just masked it for a few days. I found this thread from searching the hell out of this. This guy has the same issues and around the middle of the thread the says he had a mechanic spray injector cleaner directly in the injectors and it cleaned them and fixed his issue, My question is his was a TBI, can this be done to a TPI also?
no , on a TPI car . your best bet is to replace the injectors and FPR , when you start having wonky fuel issues. you wouldnt believe the diffrence it makes
Yeah I figured that is the best way, but I daily drive the car and have some plans for the engine down the road so I would hate to buy new 19lbs and turnaround and have to purchase larger injectors. The FPR looks new, like someone has replaced it before me. I would like to remove my injectors and have them cleaned but I can't take the car off the road for a week. I have seen that a lot of people swear by Seafoam, I think I will try a can or two of that in the tank.
i use sea foam , along with marvel mystery oil . i get good enough results with them . and it does make sense to buy the injectors for the engine you are building
I have a question regarding setting the IAC, after you remove the connector from the IAC and start the engine do you leave the jumper in pins A and B or remove before starting?
I have a question regarding setting the IAC, after you remove the connector from the IAC and start the engine do you leave the jumper in pins A and B or remove before starting?
I did yes. I had the same question and I am not sure if it was right or not. The instructions was not clear on this step. I removed the A B jumper after I shut the car off and before I restarted.
Turn on the ignition, but don't start the engine. This will force the ECM into its diagnostic mode. Wait 30 seconds to allow the IAC pintle to fully extend. Under the hood, remove the electrical connector from the IAC, then turn off the ignition and remove the paper clip jumper from the ALDL. With the IAC pintle fully extended (closed) all idle air will be controlled by the position of the throttle plates. Some manuals indicate that the EST bypass connector should be disconnected for this procedure, while some make no mention of it. While timing is a factor in idle speed, the EST should only operate as a function of engine RPM, temperature, and detonation sensor inputs. To remove all doubt, disconnect the EST bypass connector is your car is so equipped. Some TBI and V-6 engines do not have this bypass connector, and therefore must be set with no regard to the EST system. The EST can be bypassed on some cars by grounding the diagnostic terminal at the ALDL and continuing with the procedure, but the fuel mixture will be skewed to the rich side, affecting idle speed as well. In any event, the minimum air position idle speed range is wide enough to allow for some variations. As always, it is best to consult your service manual for the exact procedure for your system.
Locate the Torx screw on the left side of the throttle body. It may be equipped with a protective metal cap from the factory. This was intended to discourage adjustment. If the cap is present, use a small punch to knock it out. Once the screw is accessible, start the engine and place the transmission in DRIVE. Adjust the throttle stop to obtain 400 RPM with the transmission in "DRIVE" on an automatic transmission car, 450 in neutral on a manual transmission car, rotating the Torx screw clockwise to raise speed and counter-clockwise to lower speed. Once the idle RPM is set, place the transmission in PARK and turn off the engine.
Re-connect the electrical connector onto the IAC. Start engine. Idle speed should be governed by the ECM at approximately 600-650 rpm in "DRIVE" (for unmodified cars). Idle speed in NEUTRAL or PARK is less significant, and will be higher.
After putting 3/4 can down the PVC line(mosquito control called and thanked me) and 2 1/4 cans in 3/4 of a tank of fuel and running it through my issue is almost gone. It still has a surge, idle high, more in the morning when cold. I also was having the "flooded start" when warm, now that has gone away. I get this now in the morning when I first start the car. It seems once the car is warm or has been run it works to perfection, idles smooth, stays consistant and I have gotten a noticeable power gain! So much that @ 80mph I would run 3k RPM, now I am down 250 to run 80. Also a noticeable "launch" increase from a start. I have driven the car for 1 week on a fresh tank and it has stayed this way. I am going to finish this tank and do the in tank treatment again an maybe that will take care of the morning part.
I am going to say that after doing this that the injectors, weather sticky or clogged is my issue.
03-12-2016, 07:43 AM
