Ok, so I recently took my car to this shop by my place (VIP Performance), and I had them tune my 91 AWD Talon so I am now running an SAFC, 3" GM MAFT, Big 16g EVO 3, and 680cc Injectors. It was running just fine before I took it in, aside from Idle Surge on cold startups (which now surges ALL THE TIME), and now whenever I start it, you can hear the engine misfiring and it surges from 2500 to 1500 constantly and sometimes just dies. Ive been told it might be my Coil or the SP Wires, and I asked the guy who tuned my car and he told me he gapped the Spark Plugs at .22. Also, for some reason, whenever I try to boost in 2nd gear, it feels like a huge loss in power and doesnt boost at all, shift to 3rd and I can boost all the way to 18psi no problem. Also, if im driving on the hwy, it will misfire randomly when im crusing and my check engine light comes on, i can boost and it will go away. Im planning to take it to English Racing on Wednesday to see if they can figure out whats going on, but in the mean time, can someone shed some light on what my problem may be? Thanks!
.28 gap on your spark plugs and check for boost leaks and look at all your vacuum lines for leaks. Also, your tps or isc or egr valve could be going bad. When the guy tuned it though he should have eliminated all leaks to tune it but I'd double check it.
Ill go gap them now, but he said he checked for all vac leaks and couldnt find any. He blocked off all emissions which i was eventually going to do anyways, but I was wondering if maybe a gunked injector could be causing the problem? Ill reply back in a few after I regap them.
Okay, I regapped them to .28 and no difference really. I took out the towers one by one, and it seems like when I took 4 out it seemed to idle more steadily as opposed to when I removed any of the other plug towers. This is bugging me hardcore right now
Ill see if english can check it out. I was told by the previous owner that he swapped the old one for a new one, but it was probably just off of a car from picknpull or something. Ill post back when I get word from english about what they find.
Best source that helped me to fix my isc motor was http://www.dsmisc.com. Lots of useful information on that site, and they also offer a newer version of the motor that is supposed to work much better.
Otherwise, you can pull off your throttle body, remove the lower half section of the throttle body (held in by 5 screws) and put on an FIAV block-off plate. It bypasses the whole isc stepper motor, and most people who I have read that have done this report no more idle surge. Some people machine them and sell them on this site, otherwise you can look at ebay, search "DSM FIAV" and you'll see some things come up.
My guess would be your misfire is a product of your idle surge, only way to really check that is to have some kind of logger though.
1987 Conquest (sold)
1993 Elantra (sold)
Well as soon as I got to English, they found that my ISC was DOA. Havnt heard back from them yet but they should call me back tomorrow. But if I need a new one, Im definately going to order from DSMISC, thanks for the link bro.
Not to jack the thread but on the same note, just recently my car decided to start jumping up in idle about 4-500 rps anytime I put the car in park after a drive. It will idle at 8-900 when first start up, then drop to 600 in gear (normal). But then if i come back to a stop and put it in park jumps to like 1100 or more, sometimes it was up to about 1500??
Is there a way to reset the idle if the screw has been tampered with to much? Or can this be a ISC problem that is commen? My engine light will come on and then go back off saying idle controll malfunction. I can get the exact code if need be.
Untill I read this thread, I didnt know there was a common Idle surge and controll problem with these cars. My 1G had a bad TB bottom piece that made it surge untill it warmed up. But I didn not realize this is a common problem no both Gens.
2015 Sorento GDi. 1990 Civic Si hatch.
if you are getting any check engine light and if it continues after you have replaced your iac, tps, coolant temp sensor, maf , throttle body gaskets intake gaskets, perfomed a boost leak test and a smoke test then check cylinder compression or well heck do that at any time just for the fun of it but then take out your ecu and look for any corrosion on the big black capacitors on the main bored those are a common idle issue. and it may give many codes to if the ecu is bad.
Well finally got it back from English today, the ECU was screwed up and had stuff leaking on to it, but it has been replaced and now my car runs perfect, aside from a small amount of surge when its warming up from a cold start but its only about 100rpm so no biggie. Who woulda thunk? Thanks guys for all your help, much appreciated!
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