85IrocPrime

I have an 85 iroc 305 tpi that I recently converted from a 700r4 to a t5. I originally was having an idling issue. So I ordered a JET performance chip for a manual car. That made problems even worse. Im trying to figure out if I need an ecm out of a newer car with the combo since it wasn't offered in 85? If so how do I know the service # and broadcast combo? I think my ecm service number is 16052541 (which isnt even listed on HAWKS website as an option to buy). Is my broadcast # HLK? off the ecm (unfortunately the chip that came out was a hypertech so I dont know the factory code. Thanks to anyone who can help!

Tuned Performance

iTrader: (92)

The ecm service number is 1226870. Here is a list of bcc
http://chevythunder.com/prom_bcc_1985.htm
Blk is a 305 automatic, what is your complaint high idle ?
There was not a option of t5 with a 305 so a custom tune would be one way to go.
Stepping up and doing a faster baud rate ecm is another option. Some upgrade to the 1227165 86-89 tpi maf ecm.

85IrocPrime

When I had the hypertech chip in. It would drop very low in rpms sometimes stall, Then shoot up to around 1500 rpm. Then when I put the other chip in the engine light was flickering and it started to overheat while idling. Even with the electric fan running... This ecm would go right into my car same connectors and all? Is the ecm for a manual car the same as auto? Thank you!

Tuned Performance

iTrader: (92)

The check engine light rapidly blinking sounds like a bad prom or a prom for a different ecm. Is your speedometer cable still hooked up ?
The 165 ecm requires repinning at the ecm
http://f-body383.tripod.com/AAB/870-...pRepinning.htm

Tuned Performance

iTrader: (92)

The manual transmission tune has a higher idle. Comparison between hlk and man trans tune.

85IrocPrime

It is hooked up my speedometer is mechanical. I plan on eventually getting a custom chip burned down the road when I start figuring out horsepower gains. For right now I just want to get the car running right so I can drive it to make sure my trans swap went well. I already spent money on the chip and Im hoping I can maybe exchange it for a chip, thats for example an 87 305 tpi/t5. To solve my problem. The repinning process sounds a little over my head. This is a learning process for me. I appreciate your help!

Tuned Performance

iTrader: (92)

To change the idle speed you need a custom burned chip. A memcal or in your case prom from a different service number ecm will not work. The reason I asked if your speedometer is still hooked up is there is a speed sensor in the speedometer that sends a speed signal to the ecm. The ecm uses this signal to help control idle especially when you slow down and come to a stop.hth

84Elky

If the ECM does not recognize that a VSS is installed, you can never get things right because so many fueling and IAC decisions are made based on idling and not moving, idling but moving at less than X MPH, not idling, TPS %, etc.

85IrocPrime

Well thats good to know. I went ahead and am having a custom chip burned. I shouldnt have been so impatient and did it from the start. Thank you for all the help!

85IrocPrime

Well I got my Custom chip from Hawks motorsports yesterday and installed it. Im still having the same problem! The problem is intermittent. Initially it runs great idling smooth. Then after driving it (which seems to be after highway speeds). Coming to a stop it starts to idle surge, Starts to drop to around 500 rpm then shoots up to 1000. Then it drops lower to 400ish almost stalling (has stalled on me). Then shoots up to 1500 rpm. After shutting the engine down, cycling the key. Start it back up and its idling smooth again...Other than coming to a stop or stopped at an idle, the car seems to drive and go through the gears just fine. Ive reset my IAC and adjusted my TPS according to this guide many times. http://garage.grumpysperformance.com/index.php?threads/adjusting-your-tps-and-iac.168/ Ive adjusted the idle every which way even at a high idle (1000 rpm) it still falls back into this almost rythmic pattern of dropping down and up rpm. Ive inspected wires, connectors, vaccuum lines. Anything that may have been damaged while I was doing the trans swap and installing my headers/ custom true dual exhaust w/xpipe put on. Just to make sure its not something stupid and unrelated to the conversion. In which case Ill feel like a dumbass. I also have a fuel pressure gauge on my car and is reading at 45psi. My TPS sensor is adjusted from .54 volts at idle to over 4 volts wide open throttle. I got a new IAC and cant install it till tomorow. Ive been in contact with a gentleman at Hawks who burned my chip. Hes been very helpful but I dont think he fully understands the intermittent problem Im having. He said he took a tune from a 1987 350tpi and put it to my HLK broadcast. Im thinking my issue may be due to the fact they didnt make my car with a tpi and manual that year. GM had changed the ecm by 87 right? I dont know where else to turn. Im beyond frustrated! Ive called other performance shops and no one works on these outdated TPI systems it seems. Is it worth my while just to cut my losses and go with a complete standalone port fuel injection system like from holley or edelbrok? Thanks to anyone who can help! And sorry I had to write my life story haha.

84Elky

Really sorry for your problems. Can only suggest that you invest in some Moates hardware (http://www.moates.net/gm-19851995-c-64.html not advertising for them, it just works) to allow logging, and download and learn how to use TunerPro or TunerCat. If a mechanical problem cannot be easily identified, there's really no other way to truly diagnose what's going on under the covers without a log of what the ECM is seeing.

Street Lethal

iTrader: (16)

Okay, you need to explain yourself a little bit better. Was the problem you now have also before or just after the manual transmission swap? Meaning, did it do this with the automatic transmission as well and get worse, or did this all start after the transmission swap?

Again, this needs further clarification. You ordered a hypertech chip because the stock or original chip was giving you an issue. Now, you mention the "other" chip after trying the hypertech chip which made it worse, was the "other" chip the original chip, or is this now a third and different chip? You also mentioned an ECM with same connectors, are you also swapping ECM's? Is this the reason for your flashing ECM light, after you swapped ECM's? This quote I quoted of yours is very confusing, and if you did install another ECM, which one was it, '85 or '86 - '89?

You mention a custom chip being burned from Hawks based off of an L98. No changes being made, just took the information and put it to your HLK broadcast, right? Or HLL? Well, what happened with it when you installed it? Check engine light go on? Or did it just continue surging? Also assuming you checked your fuel pressure with the vacuum line disconnected to get 45-psi, correct? Obviously there is no lockup at this point, and it sounds like your air/fuel is completely off, especially if your running a tune based on larger injectors, while running smaller ones, unless that is the reason for the higher fuel pressure if it indeed was checked w the vacuum line connected. Your engine is running great on initial startup, during Power Enrichment and Wide Open Throttle, but surges when coming to a stop, and surges at idle speed. Turn off your engine to reset it, turn it back on and it idles fine, correct? That's because $1F has a 40 second delay when re-entering Closed Loop. If no SES light is on, then your fueling is simply out of the ECM's range.

- Rob

85IrocPrime

Thats very helpful to know thats out there. It seemed to me there wasnt much left out there for the TPI. I remember a while back Jegs had a whole section on them. Now I cant even find a set of the runners. As far as my issues I think I need to take a step back and stop being so hung up on the trans conversion. Its probably something stupid. Im just letting my impatience get the best of me. Its just hard to justify spending money on this EFI. When Im leaning more towards going with a more user friendly standalone system anyway. Because over the winter I plan on dropping a crate motor in it. Thanks again!

85IrocPrime

My car ran great before doing the transmission swap. This would be a third chip. The chip that was originally in it was a hypertech (installed by previous owner). The second chip was ordered from JET. I now realize its most likely for a TBI system even though it just said fuel injected for a manual when I ordered it. So the third chip was a custom chip from Hawks. The guy who burned the chip said that he copied the info off of an 87 with a 350. (Why he didnt just do it off a 87 305 I dont know?) But he put that tune to my HLK broadcast. My check engine light is not on and the car runs and drives great. Until I come to a stop. I talked to the service manager over at Hawks and he seems to think its a vacuum leak. So Im going to investigate that further than I already have. Since I know how things go and I did the trans swap, headers and exhaust work, and chassis work all within a couple weeks. So the chances a wire got pinched, vacuum lines got pulled off etc.. Is very possible. I never planned on changing my ECM if I absolutely have to I will. But like I said I've already wasted what a 1/4 of a whole standalone system would cost just messing with these chips and putting an IAC in it. The car runs and drives good initially and I always get it to operating temperature before I start driving. It doesnt start acting up till Ive gone about a mile down the road and come to a stop. Im not sure what vacuum line youre talking about taking off? I was just saying its a possibility that there's a leak and its causing my problem.

Tuned Performance

iTrader: (92)

Street Lethal

iTrader: (16)

The vacuum line I was referring to was your fuel pressure regulator. I mentioned this because you said you checked your fuel pressure and that it was 45-psi, and it should only read 45-psi with the vacuum line off of the fuel pressure regulator. If you keep the vacuum line on the fuel pressure regulator while checking fuel pressure then it should read closer to 37-psi. If your seeing 45-psi with the vacuum line still connected then your running too much fuel...

Your bin is set to maintain Open Loop for 200 seconds when cold, 100 seconds when warm, and 40 seconds when hot upon startup. It's in this state that you're running fine during a regular idle state. This is because Open Loop ignores O2 feedback. After driving for awhile, engine gets hot, you shut the engine then restart, this triggers the 40 second wait period and it will run fine for the first 40 seconds, but then continue to surge again once Closed Loop enables. The reason why you're running fine when you're drive around fully warmed up is because O2 feedback is again being ignored during Power Enrichment and Wide Open Throttle. This is a fueling issue, Whether you are running too much air from a vacuum leak, or too little fuel from an injector or tuning issue, then the possibilities of either amount is exceeding the ECM's ability to correct for it because O2 correction is very narrow with OBD1, and the result is you're going to get surge,..

- Rob

85IrocPrime

Well thats extremely helpful. From what youre saying it sounds like I have a leak at the regulator. I am at work right now but when I get home Im gonna see if I can't find the leak. I was under the assumption 45psi was about normal. What I read mustve been wrong. Thanks so much for your help!