having crazy fuel injector probs

[ThomasG]

I have an 89 csx that is having fuel injector issues. Car was running fine, but turbo was leaking oil. Put a T3 style turbo in place of the vnt. Seals started leaking on this turbo so rebuilt it.

Then discovered a bad vacuum leak at the intake. Fixed the vacuum leak and now my car won't even idle. Checked fuel pressure, little too high. Thought it was possibly the fpr. Took the fuel rail off to see what the injectors were doing. Injectors spray when key is turned to power. :confused2: When cranking the injectors are eratic. :confused: Unplugged injectors and tested for leaks. They don't leak. Did a visual inspection of the hep, looks fine. What is going on here?

Somebody please give me help. :o

[chilort]

What do you mean by erratic?

From what I understand, these gang fire where 1 & 3 fire at the same time and 2 & 4 fire at the same time. If they are doing that, then that is how it is 'posed to work. If not, then yeah, something is mussed up.

[ThomasG]

checked it a few times. one time 2,3 and 4 sprayed. another time 2 streamed. another all four sprayed and then streamed

[bn880]

Check wiring from injectors to ECU in detail. Check wiring to HEP, check HEP rotor too. Could be bad ECU.

[ThomasG]

found a wiring schematic for a 90 t4 which is close enough. checked injector harness, wiring continuity through ecu connector for all components and everything checks out. hep rotor looks fine.

my luck it is the ecu

[chilort]

I have very little experience with the "new" cars so I don't know all the potential problems. You might want to try http://www.pullapart.com. There aren't any that are super close to you, but you have about 5 of these within a couple hours drive. You can get ECUs and LMs from 12-35 bucks (it depends on who is checking you out and what they ring the part up as -- sometimes they ring up the ECUs as MAFs).

[ThomasG]

Would the fact that the vnt was taken out along with the solenoids have any affect? Could the ecu be getting "confused" because of this or would it be completely unrelated?

[turbovanman²]

If your testing the injectors loose, the ground isn't hooked up at the fuel rail giving you fits.


With everything hooked up, jump the coil + terminal to power, key off and read the fuel pressure, post up what it is.

[ThomasG]

Pressure at 60 psi

[turbovanman²]

Pressure at 60 psi

Thats fine, engine running, the reg should knock it down to 55 ish psi.

[ThomasG]

55ish is about where it is when it runs. can't get a good reading since the car won't idle

[ThomasG]

i can hear the injectors spray with the fuelrail in when i prime the pump

[t3rse]

Clamp the ground to the rail and see if it is still erratic.

Either way, it shouldn't be dumping fuel into the cylinder when you power the computer.

[raccoon]

check the ground on the fuel rail. I think turbovanman said so, but im saying it again

[ThomasG]

The only reasons i can think it would be spraying with power is bad asd or bad ecu. I'll check the ground again, but my dad and I went through all the wiring and it was fine.

Berry, as far as clamping the ground to the fuelrail, shouldn't I just bolt it down to the intake?

[t3rse]

Yes, but I'm saying for testing purposes, directly ground the rail.

[ThomasG]

Right. I agree. Wasn't thinking. Got up too early today.

[ThomasG]

Tested injectors with ground clamped to rail. All still spray with power on. Now they all partially mist then stream when cranking.

[ThomasG]

I'm just about ready to give up on this piece of junk.

[t3rse]

never heard that before...:lol:

[ThomasG]

ha ha. guess that goes to show i rarely actually give up when i say i'm going to.

[t3rse]

Ok fools. We need some help. I looked at this thing and this is wierdest ---- I've ever seen. When the system is powered on, the ASD goes apesheit and pulses and the injectors get a pulse of 3 volts, which of course holds them open. I can't find any shorts so I'm starting to lean toward a bad ECU. Anyone ever seen this? And I mean that when you click the key to power the fuel pump and computer, the injectors flow better than half tilt all the time. It is erradic also, one time with the door open, it didn't do it, and after messing around, if we load certain functions, like turn the fan on to draw voltage, the draw across the injector harness is less, approx 1 volt, so it pisses a straight stream of fuel. The ground is clamped to the rail, and car runs asstastic...so rich it shouldn't run.

[MiniMopar]

Yep. It's a bad ground. Check the ground between the battery and the head and also check the one from the intake to the firewall. Also make sure the battery terminals are OK:

http://www.knizefamily.net/minimopar/electrical-powerfeeds.html

[t3rse]

The only ground I didn't verify was the one from the battery to the head. Either way, it seems odd to me that a bad ground causes the injectors to fire when the computer is powered up. It seems more like a bad injector driver to me.

[chilort]

There are two '89 turbo minivans in the Atlanta South http://www.pullapart.com. Both still have the computer. Depending on who is checking people out, they cost anywhere from $12-$31 (avoid the black lady with short hair if you can because she always charger $31). If you pay in cash, it costs about 2% less than with debit or credit card.

With a 4 hour round trip and about 30 min in the JY, I think you'll have your answer. If that doesn't fix it, after you do fix the problem, send the new computer out for a new cal and have some fun.

[MiniMopar]

The only ground I didn't verify was the one from the battery to the head. Either way, it seems odd to me that a bad ground causes the injectors to fire when the computer is powered up. It seems more like a bad injector driver to me.

It's exactly what happens when a ground goes flakey for me. The ground is soft, so there is enough juice for the LM to power up and when it tries to pulse the ASD to prime the pump, the ground gives way and the power collapses. It could be a bad power feed too, though it is most often a ground. Should be able to track it down with a meter on the J2 feed and also on the power ground circuit while it is doing this.

[ThomasG]

I'll go back and double check all the grounds, especially the one on the fuel rail. All those wires just look old and decrepit.

[CDNTurboZ]

any updates on what fixed your problem?
I am having similar issues with the injectors all spraying as soon as the key is turned on.

[butchsuppe]

Try running FRESH grd wires to the ECU, injector etc. Go STRAIGHT to the batt. grd. since you have a grd problem. Every freaking grd under the hood of my car goes straight to the batt, been running like that for years now.:thumb:

[ThomasG]

I will make an attempt with the grounds. I messed around with them a little, added an extra somewhere or other. Still haven't gotten the car running. I'm wondering if it's in the injector harness itself. Could be that ground.