Firebat

iTrader: (2)

Here's whats going on. Swapped a 95 F-body LT1 with a rebuilt 700r4 into an 86 T/A. Have fixed all problems except one: car runs rich in idle and has knock retard when i quickly tap the accelerator. Has a madz28.com tune, hooker thirdgen shortie headers, 3" catback, 52mm ported '93 TB, removed egr and air, removed ccp.

This Lt1 is stock with bolt-ons. I have replaced spark plug wires and tested their resistance, replaced plugs twice - now have NGK TR-55, have new 95 KS and tested it, swapped in a LT4 KM - no change, swapped MAFs, tested for injector leaks - nothing, replaced fuel pressure regulator, replaced O2s cause one was bad. Have even swapped pcms with another car and have tried it with a stock tune, no change.

BLMs read 108 on both sides. Fuel pressure is 39 at idle, 42 with KOEO, 46 at WOT.

Compression tests with throttle blades fully open, engine warm, 4 strokes is about the same on all 8. 168-175 psi. Maf reads 6-6.5. Map reads 9.7-10.5.

Any chance it could be the opti? Anything else i should check?

1SLO6

iTrader: (8)

I think u might have a throttle body problem i beieve the 93's are different from the 94's and on....... How do u know it is running rich? with no EGR the car will do that since the gas that is not being combusted is not being re-circulated...... Exhaust Gas Reciculation......EGR.... If you are running into a knock retard problem it on a stock motor you may have to have de-sensitized since you're running it in a different car... Or problem with the motor internally. Whats the problem that you have????

Firebat

iTrader: (2)

I know its rich because i could smell it. Also, the blm's at 108 means the computer is leaning it out as much as it thinks its running rich. And i had gas in my oil after driving the car about 100 miles after the swap. I did change oil after i found that out. What the real problem is - when i tap on the accelerator while i'm going about 20-30, the car will pull timing and sound terrible and its running rich...

Firebat

iTrader: (2)

The 93 throttle body's are swappable into 95 but not vice versa. I have a 95 IAC connected to the throttle body. Only difference in the 93's are the extra tab on them for the TV cable and the IAC.

I also have a new fuel filter and walbro fuel pump.

blkchevyz

whats koeo?

not sure if that has something to do with the vacume line being off or not...

anyway it should be around 42-43 at idle with the vacume line off. and i would think it would drop more then 3 psi with it on. i could be wrong though.

streetwarrior96

O2's also might be a problem

Firebat

iTrader: (2)

Its not the O2's. Does it in open loop also before the engine reaches 140 degrees. I've replaced both them anyway because running it rich for that long killed one of them.

Firebat

iTrader: (2)

A vacuum leak would cause an increase in blms instead of a decrease. I have replaced the intake manifold gasket twice and have plugged all the vacuum lines going out before because i thought it could have been a vacuum leak. An exhaust leak would cause an increase in blms also, not a decrease.

Firebat

iTrader: (2)

KOEO - i thought meant key on, engine off

blkchevyz

i know, i wasnt saying it was a vacume leak, i was more leaning toward a fuel pressure regulator problem

blkchevyz

yeah your fuel pressure is too high. you shouldnt see more then 43 at wot, or with the vacume line off.

i dont think thats your only issue, 3 psi shouldnt max out the blms, but its not going to help

Firebat

iTrader: (2)

i think fuel pressure was 42-43 with the vac line off. I'll look at fuel pressure at wot again. It does seem funny that those two would be different.

Firebat

iTrader: (2)

Just checked it out. Its reading 47-48 with vac line off. Thanks guys for your fast replies, much better message board than some others i have been at.

blkchevyz

glad you got it figured out

Firebat

iTrader: (2)

actually 46 or 47 is at the high end of an acceptable range at WOT.

Another weird thing is going on. If i unplug the MAF then start the car, it will idle but will die if i give it any throttle.

blkchevyz

mine has always done the same.
guess with the few mods you have it still threw off your speed density tune.

funny thing is my friends 95 will run fine with it unpluged.

Firebat

iTrader: (2)

Another funny thing is that the IAC is pretty low at 550 rpm idle. It dropped to 5 after letting the engine run for a bit.

blkchevyz

might want to close the throttle body blades just a little to get that back up.