OBD1 limited tuning ability

M Wyson · August 4, 2020

Is there an aftermarket computer I can put in my truck to give me more tuning ability? My 1990 OBD1 ECM is limited as to what I can do with it. It's an antique. Is there a later model ECM I can swap into this truck? I don't really want to go backwards and install an HEI and carburator but it's what I'm tempted to do. I've had this truck for 750,000 miles. I've been lucky so far to not be broke down and it's virtually been trouble free. The check engine light comes on and I start replacing parts then it goes off for another 30,000 miles or so. I just hate the fact I can't plug a laptop into it and see what's going on. (Yeah I know about Moates.com but that's a lot of hassle to still have limited tunability)

riverbanks · August 4, 2020

Where do you think you can improve it?true dual exhaust,e-fan, higher gear ratio are a few things you can do

CamGTP · August 4, 2020

Nope, nothing you plug in will do what you want.

I would go with a Holley Sniper system or similar. They are a fuel injection carb looking thing with sensors and a mini handheld computer that I believe you can also plug a laptop into.

M Wyson · August 5, 2020

Doesn't the ECM control other things like the a/c and shift points and convertor lockup?

CamGTP · August 5, 2020

Yeah.

I was just giving you an option. Standalone control systems is the only real way to get the adjustability you want. It would mean other things would have to be either gone away with or made function another way. Like a standalone transmission controller or making it manual valve body and figuring out the AC system.

It's either live with what you got or dive off the deep end with mods. Or just slap a 5.3/6.0 and have gobs more power/torque and fuel mileage compared to a TBI truck.

LDM · August 12, 2020

I've been doing OBD1 tuning since the late 90s. Still do it today on my 89 and 94 Camaros. You can get an OBD1 interface and the DataCat program from www.tunercat.com and be able to plug in and read all the codes you want. DataCat is TunerCat's updated version of the old TTS Powersystems data logging programs and supports just about every one of the OBD1 truck ECMs from 88 to 95. You can also buy the definition file and TunerCat tuning program to tune your truck as well, although you are also going to need some additional equipment such as EPROM burner, adapters, and EEPROM chips or an Ostrich to allow real time tuning. Gets a little pricey if you want to do real tuning but no where near what it costs for OBD2 tuning.

There really is no sense in spending money on an expensive aftermarket ECM when the current one still works just fine. However, unless you have done ECM/PCM tuning before, its not going to be something plug and play. You are going to have to spend time and effort to learn what you are doing or risk damaging your engine and/or ECM.

Edited August 12, 2020 by LDM

M Wyson · August 14, 2020

Thanks. Yeah I've looked into it and seems to be a lot of stuff to get and a lot of stuff to learn. I think I'll just find someone to burn an Eprom for me. I just bought a zz4 Vortec engine so I need to eliminate the egr

LDM · August 14, 2020

14 hours ago, M Wyson said:

Thanks. Yeah I've looked into it and seems to be a lot of stuff to get and a lot of stuff to learn. I think I'll just find someone to burn an Eprom for me. I just bought a zz4 Vortec engine so I need to eliminate the egr

If you are going with a ZZ4 I would probably just recommend the carb route. You would need significant tuning to get a 90 ECM to work with a ZZ4 engine, they have much better heads and a far different cam/lift profile than the old stock TBI engine. If you really do want to go EFI that has self tuning ability, the Holly Sniper EFI is suppose to be able to self tune without a laptop. Not sure how well it works and its about $1400 so it is definitely a lot more costly than a carb.