maxont

Passenger side bank is running very lean (gets hot very fast).
At first i thought it was maybe an internal vacuum leak from the intake manifold. I did the finger over both the pcv hole and the breather on the other side... it had a bit of vacuum. so i figured that was probably it.... took it apart and replaced the gasket and what do you know, it didnt fix the problem and the vacuum is still the same. before i had did all that work i tried a couple things to see if they helped and heres a few...I pinched the return line to see if maybe i wasnt getting enough fuel on that side somehow, didnt do anything. all injectors checked out just fine. starting voltage testing the injector wires.. this always confuses me. passenger side gets 12v on both wires with key on and ecm in as does the drivers side. with the ecm out the passenger side gets 12v on each wire while the driver side gets 0v on either wire. ohming the passenger side i get 15ohms on one wire and 21ohms on the other. driver side i get nothing. the driver side plugs are golden and look great while the passenger side plugs show lean fauling.

at this point im at a loss of ideas... if someone could maybe refresh me on how to properly voltage and ohm test my injector wires that could help, and also any other ideas of why this passenger bank is running so lean.

Thanks

Air_Adam

What engine is this?

How do you know one bank is getting hotter than the other? What part speficially is getting hotter?

maxont

tpi 350, entire passenger bank gets super hot 20 seconds after startup (header) while driver side is still very cool. driver side plugs look great and passenger side looks lean fouled.

RBob

iTrader: (1)

Check the INJ1 and INJ2 fuses in the fuse block, one is probably popped. Both sides should have 12 volts on them with the key-on and ECM removed. Note that it sounds like the drivers side has the issue.

If it isn't getting hot then those cylinders aren't firing.

It can also be helpful to list the MY of the vehicle along with the type of induction system (TPI, TBI).

RBob.

maxont

i have checked the fuses already they are both good. the driver side plugs look great which leaves me to beleive that side is fine. its the passenger side that has fouled plugs. and before all this happened that side would never heat up that fast

maxont

This whole problem started after i took off from a stop sign, hitting about 4k rpms and then the motor just took a crap on me and wouldnt rev past 2.5k. Its like the computer is not letting the distributor advance now and/ or the knock sensor is picking up a knock and retarding the timing. im not sure if the passenger bank is running lean because of this or what but the computer is not putting any codes. any ideas? Theres 1 cylinder that recently burnt through a spark plug wire which i replaced along with the plug... didnt help the problem. The car is pretty much undrivable because of its terrible lack of power do to maybe no advance/lean bank im just not sure what is going on.

Air_Adam

20 seconds after startup, the headers SHOULD be too hot to touch. Thats normal. I agree with RBob, theres something wrong on the side that is not heating up. Either no spark (unlikely to happen to only the odd# plugs) or no fuel (more likely).

maxont

i shouldnt have been so stubborn in my own opinions... you guys are totaly right. The driver side isnt firing... i just took off all the injector wires with the car running and nothing changed. take off 1 on the passenger side and the car about falls on its face. gonna start trouble shooting the driver side tomorrow for spark and whatever else i can think of. any suggestions would be great. thanks much guys

Air_Adam

If you can take the injector connectors off with no change, that means the injectors aren't firing for some reason. Its not going to be a spark problem, because your car has one distributor and one coil. If it was a no-spark problem, it would be spread out over the whole firing order, not just the odd numbered plugs.

Check for electrical power at the injector connectors when the engine is running, see what you get with a multimeter. Does it match the working injectors' readings? If all the injectors on one side are not firing, its likely theres an electrical problem related to just that one side. If each side is run off its own fuse, check that. If thats ok, look at a wiring diagram and start looking for a bad/broken ground. I don't know how the wiring harness on a TPI is set up specifically, but for every power wire there is a ground somewhere. When multiple components (ie. your injectors) in one 'branch' of a wiring harness just suddenly stop working, its almost always either a blown fuse or a ground problem, because they are usually all tied to one fuse and one ground.

Start there.

robguitargod1

iTrader: (4)

I have an L98 that's doing the exact same thing!...........My problem is the passenger side though, the injectors are simply not firing.

It runs like SH I T and shakes very badly. After 10 or 20 seconds I kill it and feel the exhaust manifolds. Driver side hot like it should be, passenger is cool to the touch.

Timing is set at 6* initial, and all is well besides the passenger side injectors not firing. I've checked the inj1 and inj2 fuses, and both are fine.

I bought this formula 350 not running, tore the engine apart to make sure it wasn't trashed, and am not ready to fire it up when this nonsense happens......

I even cleaned up the rear ground connections on the back of the heads while the engine was out.

Any ideas?!?!

sofakingdom

iTrader: (1)

Shorted injector on that side

Check em with an ohmmeter; should be in the 15 - 16 ohm kind of range, and all within a half ohm or so. Odds are, you'll find one that's DRAMATICALLY lower resistance than the others.

robguitargod1

iTrader: (4)

JUST did! All 16 ohms. Man, it's gotta be something common for all of them to not be firing..........

robguitargod1

iTrader: (4)

I refuse to believe they're clogged since the drivers side are the same age and in the same condition.

I know one side of the injectors should be 12V, and the ECM pulses ground on the other terminal. Haven't tested any of that yet, but the inj1 and ing2 fuses are all good.

sofakingdom

iTrader: (1)

Noid light results?

robguitargod1

iTrader: (4)

I'm gonna get to it ASAP. I'm really curious to see if the injectors getting power and/or ground pulses.

RBob

iTrader: (1)

The '86 - '92 TPI ECMs have just one injector driver. They do have two pins to drive the injectors. So you can have a bad wire/terminal and lose a bank.

There is also usually two injector fuses (INJ1 & INJ2). One for each bank that supply power to the injectors, the ECM provides the ground to open them.

RBob.

robguitargod1

iTrader: (4)

Already checked fuses, they're good.

I've read quite a few threads on this problem, but haven't seen a fix yet...

RBob

iTrader: (1)

Yup, a wire from the ECM to each bank... Each wire provides ground to fire a set of 4 injectors...

RBob.

robguitargod1

iTrader: (4)

I'm off after tomorrow so I'll be testing more soon.