88 Suburban 5.7 TBI chip

[BR@NDON]

My suburban isn't passing emissions. The guy that I bought it from said he "thinks" it has a chip in it. I'm learning TBI with this truck so - any pointers on where to find the chip and how to identify it?

 

[Jims86]

My suburban isn't passing emissions. The guy that I bought it from said he "thinks" it has a chip in it. I'm learning TBI with this truck so - any pointers on where to find the chip and how to identify it?

Pull the glove box, and behind and up will be the computer. Pull it out, and take the access plate off of it, and look inside at the larger of the 2 chips. see what it says on it.

 

[BR@NDON]

Large chip has a red sticker on the top that says "Super Chip" The outside housing has a RN trademark laser etched on it. Bottom side of the chip has a paper sticker with 8712A AMNR written in handwriting.

So obviously it's not factory- do those numbers help identify anything?

 

[Jims86]

Large chip has a red sticker on the top that says "Super Chip" The outside housing has a RN trademark laser etched on it. Bottom side of the chip has a paper sticker with 8712A AMNR written in handwriting.

So obviously it's not factory- do those numbers help identify anything?

That chip is for a 4.5L Cadillac Seville.

 

[BR@NDON]

That's interesting. Is it possible that this is the cause for extremely high CO and above average HC?

 

[bucket]

That chip is for a 4.5L Cadillac Seville.

Huh? That could run a TBI 350?

 

[Jims86]

That's interesting. Is it possible that this is the cause for extremely high CO and above average HC?

I'm not sure about that, but I do know that it probably deosnt run that good, and it probably fried your catalytic converter.
There is a possibility that super chips tuned it for the 350, but its interesting that they would use that as a base.
do you have a smog pump?

 

[Jims86]

Huh? That could run a TBI 350?

Yeah, not very well....would fall flat really quick, but with the proper 350 injectors, it MIGHT idle ok, along with a lean part throttle cruise.

 

[BR@NDON]

The engine has plenty of power. My brother has a 91 suburban and mine puts his to shame in the muscle end of things.

Any sources on getting a stock replacement prom chip?

 

[BR@NDON]

Sorry, I didn't answer your question: Yes, I have a smog pump, as well as the A.I.R. system, EGR, and I have installed two Magnaflow Cats behind the headers. It has true dual exhaust.

 

[Jims86]

The engine has plenty of power. My brother has a 91 suburban and mine puts his to shame in the muscle end of things.

Any sources on getting a stock replacement prom chip?

Ebay is your best bet, or even a wrecking yard.
Super Chips just used that chip as a base then...as long as its tuned for the 350, its ok.
you should pull your plugs to see if its running rich.
Any other info on the engine would be good...has it been built up in any way, or is it stock?

 

[Jims86]

Whoa.....Wait a minute....headers?
What kind, and if they are not shortys, do you have a 1 or 3 wire oxygen sensor?

 

[BR@NDON]

I've done quite a bit over the last month with the truck, so I'll give you the low down -

The truck's original owner had the headers and chip done probably in the early 90's. (not sure) The guy I bought it from was the second owner and didn't know very much about the truck. He owned it for 10 years and let his wife drive it. All he said was that he blew a head gasket once and that he thought the car had a chip in it.
After buying it, I changed the oil and plugs, cap and rotor. And ran over to the emissions testing station as you can't transfer titles without passing the test in AZ. I failed HC, CO, and Nox. Also failed the evap test. I replaced the plug wires and at that point the distributor module died on me. I replaced that and the pickup coil, and remote ignition coil just to be thorough as the car needed a major tune up anyway. I swapped the canister out for a new one. I also had the 2 magnaflow cats put on and set the timing at 4btdc. I bought an o2 sensor but forgot to put it on the truck and went and failed my second emissions test. HC, and CO were worse and I passed the Nox and evap this time. I put the o2 sensor on tonight. This brings me to why I am even looking at the chip. My issue is that I need to pass smog LOL!

Thanks for your help so far Jim. As far as I know, the internals of the engine are stock. The throttle body is stock. It squirts plenty of fuel. I need to check the EGR but after that, I'm not sure what else could be causing the emissions failure.

 

[BR@NDON]

Whoa.....Wait a minute....headers?
What kind, and if they are not shortys, do you have a 1 or 3 wire oxygen sensor?

Long tube. It's a one wire.

 

[Jims86]

Long tube. It's a one wire.

Okay...You NEED a 3 wire heated o2 sensor for a 95 truck. your one wire o2 is not close enough to the engine, therefor, cools off, and keeps kicking the computer into open loop.
The 3 wire sensor can be added easily wired up. the black wire is the signal wire, whichnis the wire you currently have,mand the 2 white wires: one is ground, and the other is to switched key power...doesnt matter which.
and set the timing back to 0*, and make sure you have a 195* thermostat... dump a 1/2 gallon of laquer thinner to a 1/4 tank, and go drive the **** out of it in 3 rd gear for about 10 miles, then fill the tank, and see if it passes...its really a tossup at this point,mbut you have a better chance. Maybe you can explaine to the smog guy that you are trying to correct some stuff that the previouse owner did, and he may do a free sniffer test to see if it will pass.