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How far do you have to go before a chip is necessary for a 89.
Can they burn a chip just to make the car feel more powerful and better response after a few mods.
Im talking to PCMforless and he will burn me one.
I eliminated the air pump, EGR, installed180 stat, want the fan to come on at 200 and off at 185, moved IAT, de-screened the MAS and am getting true duals, opened up the air filter lid and would like to get rid of the vats.
You will clearly need a new chip to have your engine eliminate the EGR. Disabling the EGR will not stop the ECM from trying to use it. The new software will have no EGR to start with. De-Screening the Mass Air Flow sensor might make a bit more power but I have heard it really doesn't make any big differences.
Many years ago I bought a device called a GTech Pro and it was able to calculate the horsepower of the Corvette as long as you enter the accurate weight. It also had shift lights that were feeling the torque output of the engine to decide when to shift. The very best part was that you can see any differences from before and after readings with the GTech Pro. I replaced the Catalytic with a higher flowing unit and then Installed a Cat back Chambered Pipe exhaust system. It opened up the exhaust and helped it flow more. The power gains was less than 14 hp for both after installation. This is handy as now I knew my engine was helped by this modification. I use the GTECH when working on a carbureted vehicle and it helps me get the best tune possible for the engine.
I just got one from PCM's for less. I'm going to install it this afternoon. Turnaround time from order to delivery was something like 3 days. I think I ordered it Sunday morning and it was at my door on Wednesday last week.
They have an online form you fill out after you order that will have you list your current setup including thermostat temp, eliminate VATS, etc. Since my car is bone stock except for thermostat temp, I just wanted the fan to turn on at a lower temp. My order states something like "for stock or bolt on parts only".
Again, I'll let you know how it goes in a couple of hours.
Last edited by SmokinBlack; Sep 18, 2021 at 10:30 AM.
Just finished my install. Everything went as expected. The only thing that I did different is that I fully removed the cover from the ECM to get the new PROM assembly back in. It was super tight trying to get it through the access door without taking the cover off.
New fan settings are exactly where I wanted them. Going to grab lunch and then take it for a drive.
I'm surprised that for a 1227165 that it's NOT the suggested install procedure!
Do they actually 'imply' only removing the PROM cover?
For '90 and later it would be interesting to see an owner post thoughts of their install.
Did they offer only this or will they modify a supplied OEM/GM PROM?
No, I'm sorry if I was unclear in my first post. They do state in their install instructions that "Some early computers require removing the case cover". However, I had watched a couple of videos online where people were installing them just through the access cover. I'm not sure how they can do that. It is tight.
Last edited by SmokinBlack; Sep 18, 2021 at 03:34 PM.
How far do you have to go before a chip is necessary for a 89.
Can they burn a chip just to make the car feel more powerful and better response after a few mods.
Im talking to PCMforless and he will burn me one.
I eliminated the air pump, EGR, installed180 stat, moved IAT, de-screened the MAS and am getting true duals, opened up the air filter lid and would like to get rid of the vats.
If you want to remove the EGR and not have a check engine light, you'll need a tune (or a chip with a "tune" in it)
If you want to "get rid of VATS, then you need a chip with a new tune in it.
The rest of the stuff, it won't matter at all. I also have an '89 (that I turned into a Kart). I've removed all of the stuff you want to (except VATS) and it runs awesome. I've installed dual 2.5" exhaust w/no cats, straight through mufflers, descreened the MAF, no smog pump, 160 stat (car came with it) and no air filter at all. Runs great and made 240 RWHP and 340 RWTQ....not bad for an engine rated at 240 CRANK.
I recently did an intake ONLY swap, I removed the TPI and installed an SLP T-Ram intake and it picked up 35 RWHP with the intake only and no tune (chip). A/F ratio was great through the entire pull. So, you'll need a tune for the EGR w/no CEL, and the VATS, but none of the other stuff.
From: Liliha Bakery stuffing my face with coco puffs!
Memcal adapter sold by Moates doesn't extend further than the chip socket as compared to the PCM of NC and may provide more room when trying to install through the little access cover. TBH, it's not like you're going to be removing it and installing it repeatedly so if you can't install it through the access cover opening, I would reinstall the case cover after installation of the memcal/memcal adapter.
Last edited by stew86MCSS396; Sep 19, 2021 at 05:44 AM.
PCM is doing a piggyback chip, I have a standby chip from Ed Wright that is similar.
For the mods you have, you do not need a new chip tune. You do not need a tune to eliminate EGR, it can be done with the diode trick. For the VATS they used to make a bypass unit, but I haven't looked in some time.
However if you want to get a tune anyway, they can just turn off the Code 32 function which effectively eliminates EGR as well.
Generally I tell people if youre going to continue to mod, don't pay hundreds of dollars for a tune unless the combo requires it. That is usually when you've done a lot of intake mods, or changed the cam.
The ecm is looking for the EGR diagnostic switch to either be closed during startup, or to be open (indicating no flow) for 4.5 seconds when EGR is active under specific conditions in order to set the code 32. So to avoid the error, you want the EGR diagnostic switch to remain open during startup, then close (indicating flow) after startup so that it appears that the EGR is flowing when it is active and is being monitored. So if you can get the modified circuit with diode to resemble an open circuit during startup, then close the circuit afterwards, it will work.
I didn't bother to search for an example of the modified circuit with diode, but assume that it is possible to achieve the desired behavior. I would never bother with this since it is so easy to correct via programming. Ignition timing may be a bit excessive in some rpm/load regions without EGR, so tuning is a good idea anyway.
Last edited by tequilaboy; Sep 20, 2021 at 03:23 PM.
What is the diode trick, hear about it but never any details.
Basically wire a diode between the command line and temp sensor. It will pull the EGR temp switch to ground when the solenoid pulls in. That is the feedback the ECM is looking for. The ECM will see it there and won't set the code.
I am receiving a "piggyback" chip for my 1988 today. It is coming from TPIparts.net. Cost was $106 shipped. I had them reset my fan temps, do away with the egr, VATS and cold start injector. We will see how it works. Using this, if you want to go back to everything factory, just take this part out.
aftermarket chip time ?
