Warlocksirix

I did a search and not sure what to look up because it could be a number of issues. It feels like a loss of power when bliping the throttle at idle, it sucks in air but for about half a second to a second it sounds like it'll die but it revs up after the initial loss of power. I plan to do a few other mods after reading some other threads on the forums.

Orr89RocZ

iTrader: (20)

Could be dirty iac valve. Slight stumble as rpms drop and try to stabilize seems idle valve related. Mine did stuff like that once. Clean the tb and iac

Warlocksirix

New IAC, tore the entire TB apart and cleaned everything. New MAF as well and still has weird idle at warm 110+ temps or after running for about 30min it throws a code and wants to die. It's killed 2 fuel pumps already. But after looking over everything I noticed it has a weird choke when bliping the throttle at idle as well as slamming on the gas at a dead stop. It seems to have a pause in power getting the engine off the line on throttle hit, give a .5 to 2sec pause and it spins the tires but it seems to dog on WOT from takeoff.

Orr89RocZ

iTrader: (20)

91 should be map not maf. Shouldnt be killing pumps either. Fuel regulator and filter good? No restrictions there to overwork pumps? Injectors not goin bad are they?

Also check o2 sensor

Warlocksirix

yea might be map, it's the one attached to the rear of the TB. Replaced all the insides of the FPR with new whe I replaced the valve under the TB, can't remember the name off the top of my head. New filter on replacement of pump. How do you check the O2 and injector for correct power table?

Orr89RocZ

iTrader: (20)

O2 codes showing up? How old is it? Does car run ok when cold started?

Injectors let car warm up and then take off the harness clips and ohm meter the injector prongs. See if its near 16 ohms

Warlocksirix

Warm up as in closed loop? Car is a 1991 5.0 with 120k and it runs like a raped ape when it's ice cold outside just runs like garbage once the engine hits closed loop. Cant remember the code i'll have to pull it.

Orr89RocZ

iTrader: (20)

Doesnt have to be closed loop to check injectors as long as they are warm.

But to me it sounds like a closed loop issue now that you mention it run strong when cold and out of closed loop

Get a new o2 sensor and inspect the wiring around that sensor and see what it does.

Warlocksirix

Just pulled the codes

12 Diagnostic mode / ECM functioning No reference pulses to ECM.

32 MAP (Manifold Air Pressure) sensor
circuit open OR EGR fault OR Barometric pressure circuit shorted.

46 Fault in VATS (Vehicle Anti Theft System) OR fault at power steering
switch (4 cylinder).

Orr89RocZ

iTrader: (20)

Hmm also may have some electrical issues. Egr valve maybe bad too. I am not sure but thats a place to start

Warlocksirix

I replaced the EGR that's when I replaced the FPR and the ATS. Sorry for all the trouble but yea I replaced a ton and it's still giving me problems.

SbFormula

Can you monitor with a DataMaster style software. That would give you an idea of what the sensors are reading and what the ECM is doing. Also the fuel pressure and vacuum readings could give you clues. Among the ton of parts you have changed, have you changed the old Multec injectors? They are prone to failure after all those years.

The trial and error part replacing approach is not a very effective way to fix TPI problems and it is nerve-racking for its owner. If you plan on keeping the car, invest in a software for data logging and a ALDL cable as well as fuel and vacuum gauges. The software can be run on a basic laptop and is user friendly. This has helped me through the years diagnosing problems that would have driven any local mechanic out of their mind and also cost me a fortune in trial and error part replacing approach. The Multec injectors are an example and also I had an intermittent knock sensor problem! Only with DataMaster monitoring was I able to snap shot symptoms and evidence that led me to the problems.

And ohhh! The ECM codes are not always reliable. The "code such and such you have to change such and such part" approach is costly and frustrating. You need a diagnosis chart that you probably can find online. Each code has it's sometimes complex chart for problem solving. But remember that sometimes the ECM throws a code as a symptom of an underlying deeper problem.

Best of luck!

Warlocksirix

http://www.reddevilriver.com/aldl.html will something like this work? Also thanks for the information Formula. I replaced what would normally be bad on a vehicle so it was not much concern as they were all *aged parts. It's spending 600 on a replacement engine that would be more frustrating as I have pretty much every tool I would need for mechanical work other then the OBD1 tech tools. I plan to use the https://www.thirdgen.org/forums/tpi/...free-mods.html section on the forums for a few other mods while I am busy tearing the injectors off to replace them.. being OEM they are more then likely faulted.

SbFormula

The cable sounds about right. I got mine years ago from OBD Diagnostics http://www.obd2allinone.com/aldl.asp. As far as the software I use DataMaster on a laptop http://www.ttspowersystems.com/about.html. They also have cables. But I am pretty sure there are tons of review about software so you can get the best option for your needs. Most of the software have trial free trial period. For the injectors I got Bosh from https://secure.fuelinjectorconnection.com/shop/ and they wrok fine. Had to retune a bit as they are more effective and have less lag at low PW.

As far as tuning there are multiple options such as EBL http://www.dynamicefi.com/ or http://www.moates.net/gm-19851995-c-64.html. I went with Moates set up with emulator and CATS Tuner RT which works great. But if I'd have to do it all over again I would go with RBob's EBL.

Never give up!