According to the Crossfire forums, replacing the existing fuel pump with a 1985 pump is a easy mod that many have done and recomend.

I just finished installing a '85 fuel pump in my '82 Vette. The good news it it works! The old FP looks like it was the original and was in terrible condition.

She started right up and ran for 1 minute then died.

The Bad news is, fuel is gushing out of the rear injector. I'm fortunate I didn't catch fire!

It looks like the gas is coming out of the top of the injector and not the bottom where it attaches to the manifold.

This injector is the original. I had to replace the other (front) recently because it was leaking. I was told the rear was ok, but may need replace in the future. I assume the new pump has exposed a weakness in the old injector.

Questions:

Is the pressure regulated to 13PSI prior to supplying the rear injector?

Does it look like I'm going to have to replace the rear injector, or is it possible I just need to adjust the pressure coming into the rear injector.

How hard a job is it to replace of of these?

Thanks!

 

The rear injector is the one that regulates the pressure. It has the regulator built into it and steps down the psi.

It sounds like you may have to rebuild it or it could be just the gasket. Exactly where is it leaking from? The seal area or injector area. If its the seal area try tightening down those bolts.

Just a break down for you. You will notice the TBI on the rear is different...the rear part houses the regulator spring. Then you have the upper chamber body and the flow to the injector it self. Injectors can be replaced. Other sections can be rebuilt.

Jim

 

Ok, correction.

The leak is actually the FRONT injector. This this the one on the passenger side nearer the front of the car and where the gas from the pump comes in.

It appears that the fuel is pouring out around the fuel outlet passage gasket. It does not appear to be leaking around the fuel meter cover gasket.

It appears the FOP is the feed to the rear injectors which is getting no fuel due to the massive leak.


It looks like I'll be buying a FOP gasket and probably a fuel meter cover gasket while I'm at it too.

Also, I found that you need to be careful in tightening the bolts. I stripped one so I also need to get a tap set

Thanks for response.

 

Ok, I'm feeling worried. I just ordered the 85 fuel pump to install this weekend. I have rebuilt my throttle bodies so hopefully I won’t see the same thing.

I remember not seating the front injector just right when I rebuilt them and gas just poured out of that injector holder. I took it back apart and noticed I didn't align the pin into the groove...all better the second time.

If you need any help finding gasket kits I got mine from GMPartsdirect.com but I found out AdvancedAutoParts also carries them online.

 

Zixx,

I just spoke with the Dallas area Vette expert and he seems to think changing the gaskets ought to do it. He said that the gaskets should handle the extra fuel the '85 pump is delivering.

I actually didn't strip ant bolts btw. There are 2 different size bolts and I put the smaller one in where the longer one needed to go.

I keep repeating.. "events that do no kill you only make you stronger" all day... If this don't get me down, I'm going to be a freakin Arnold S.!!

 

I feel your pain. I've bought a great car but it has its quirks so my quest has been to list them and start fixing them. I think the list growing because I have this need to fix the smallest things.

The first three weeks weren't satisfying at all...actually felt I was failing somehow. Now I've conquered some things I thought I would never do like rebuilding the suspension......@$(*$(*&@# pickle fork and hammer were very close to becoming a set of lawn darts. Now I have painted and cleaned all the wheel wells, frame (90%), calipers, new springs, shocks, etc. Lots of little nuts and bolts replaced to unbubba some things.

The cross fire is the great mystery still...replaced with over bored rebuilt units, injectors, etc. Replaced every gasket but still feel like I have a miss. After having the car scoped we're heading towards a bad distributor as the culprit....we'll see, I've ordered a new one. Fuel is next weekend just because it seems like a win win addition to the car.

I give myself another month or so, if it's not right...crate motor time but I'm convinced I can do it as it runs well certain times so it’s doable.

 

PS If there's an expert on cross fires in Dallas please let me know. I've learned to balance the TBs with a manometer but until I clear up the miss near idle I'm still not satisfied. If the pump and distributor don't fix it then I'll be looking for an expert to assist me.

 

These crossfire injection horror stories make the whole thing look like a bad idea to begin with. Why the hell did GM use that thing?

 

Zix,

Don't worry about it go with the 85 pump. Stories of leaks are rare....as a matter of fact this is the first i have heard of it. I don't think Yanks problem was caused by the pump.

The new pump will most likely resolve your "miss".


The key is balanced TBI's. If you want check them. Hook up the manometer to the front TBI first. SEE if its close to 6 inches of water. Then hook up the back one and check it. So long as they are close and balanced you are okay. Did you make sure the car was warm, wheels are caulked, car is in gear (second person). when you checked?

Usually at balancing throws of the TPS...did you set it to .525 volts?

Read this for starters.. http://corvettefever.com/techarticles/4688/index.html


Jim

 

Where is it leaking exactly? from under the lid around the injectior or under the injector wiring connector???

Crossfire horror stories? how many crappy running q-jets are out there, or leaking sight glasses in holleys...and ...and...and...

Here's a pic, please temm me where exactly it's leaking


Front Unit (passenger side)
1 Screw & Lockwasher (2)-Fuel Meter Cover (short)
2 Screw & Lockwasher (3)-Fuel Meter Cover (long)
3 Fuel Meter Cover & Accumulator Assembly
4 Screw & Lockwasher (4)-Diaphragm Cover
5 Cover-Spring & Diaphragm
6 Retainer Spring
7 Spring-Accumulator Diaphragm
8 Diaphragm Assembly Accumulator
9 Gasket-Fuel Outlet Passage
10 Gasket-Fuel Meter Cover
11 Injector-Fuel
12 O-Ring-Fuel Injector (small)
13 Filter Fuel Injector
14 O-Ring-Fuel Injector (large)
15 Washer O-Ring Back Up
16 Fitting-Fuel Inlet
17 Gasket-Fitting
18 Fitting-Fuel Return
19 Gasket-Fitting
20 Screw & Lockwasher (3)-Fuel Meter Body
21 Fuel Meter Body
22 Gasket-Fuel Meter Body
23 Valve-Idle Air Control
24 Gasket-Air Control Assembly
25 Throttle-Body Assembly



Rear Unit
1 Screw & Lockwasher (2)-Fuel Meter Cover (short)
2 Screw & Lockwasher (3)-Fuel Meter Cover (long)
3 Fuel Meter Cover & Regulator Assembly
4 Screw & Lockwasher (4)-Diaphragm Cover
5 Cover-Spring & Diaphragm
6 Spring-Pressure Regulator Diaphragm
7 Diaphragm Assembly-Pressure Regulator
8 Dust Seal-Pressure Regulator
9 Gasket-Fuel Outlet Passage
10 Gasket-Fuel Meter Cover
11 Injector-Fuel
12 O-Ring-Fuel Injector (small)
13 Filter Fuel Injector
14 O-Ring-Fuel Injector (large)
15 Washer O-Ring Back Up
16 Fitting-Fuel Inlet
17 Gasket-Fitting
18 Fitting-Fuel Return
19 Gasket-Fitting
20 Screw & Lockwasher (3)-Fuel Meter Body
21 Fuel Meter Body
22 Gasket-Fuel Meter Body
23 Screw & Lockwasher w/ Retainer (2)-Sensor
24 Sensor-Throttle position
25 Valve-Idle Air Control
26 Gasket-Air Control Valve
27 Throttle Body Assembly

 

The leak is on the front injector. It appears to be around:
9 Gasket-Fuel Outlet Passage

It does not appear to be around:
10 Gasket-Fuel Meter Cover

There are no other leaks on the front injector that I could see.

The rear injector did not leak at all.

After I installed the new FP, the car started right up and ran for about 1 minute before it died. I assume it did not leak initally or leaking very little, but I cannot be sure. The leak was such afterwards that fuel spurted out at the fuel outlet passage area.

I ordered a AC Delco TBI gasket kit this morning. If all goes well I will have it installed by tomorrow afternoon.

What should I do when I install to make sure the gaskets seat properly? I have already cleaned the two surfaces with a soft cloth and some degreaser.

This injector was rebuilt recently so I'm at a loss why it leaked. It did not leak with the dying FP.

Thanks for the response!

 

Maybe there was an error made when rebuilding it or the little gasket #9 positioned poorly leading to it blowing out, it's hard to say without actually looking at it. If you have the injector cover off, check the surface for nicks or anything else out of the order. If you remove all the old gasket material and just give it a quick wipe with brake cleaner you should be fine

 

Because the Rochester/Delco guys hadn't yet managed to make a TBI that would work on a V8, the TPI system wasn't ready, and the computerized carb was a POS.

 

So they shoulda just stuck with the M4ME, which obviously worked fine. I think it was because of pressure from other auto makers moving to fuel injection that forced GM to push out a lackluster form of it.

I would have rather seen mechanical fuel injection rather than "missfire injection."

 

I don't think it was competition, I think it was the EPA. If it was just competition, they would have soldiered on with the M4ME Quadra-crap until the TPI system was ready (or at least a twin-injector TBI).

 

Gaskets installed, now noticed a major leak coming out of the
fuel pressure compensator assembly



Am I looking at a new TBI at this point? I know that many people have switched to a '85 pump but at this point I'd take a '82 if I knew it wouldn't leak.

I'm open to suggestions.

 

You can rebuild that side as well....the gasket kit you bought likely has the gaskets you need. I do know you're not suppose to spray any cleaner into that assembly...not sure why but I read it somewhere.

Be careful taking that side apart, it's spring loaded so I'll see if I can find the instructions. I think it was the Autozone website that actually had the instruction. More to follow.

 

Article

This will show it how to do it, and you could even do this mod while you're at it.

 

Won't matter if you had the 82 or 85 pump. The driver side TBI steps the psi down. All your probably getting is 13 psi in the passenger side TBI. Your going to have to fix it. Its probably another seal.

jim

 

the diaphragm is most likely shot, buy a TBI rebuild kit, it's just a bunch of gaskets, o rings and steel rings..these TBIs are rediculously easy to rebuild. Install all the new seals, rings, filters and stuff..most likely the higher flow pump put more strain on the system causing the old stuff to leak.

The 2nd TBI regulates the pressure, there's no way the pressure is higher unless you have so much flow that the regulator itself or the return line is restrictive..or if there's a pinch in the return line somewhere, might want to check that. Pumps create flow, not pressure, pressure is the result of trying to force a volume (flow) through a restriction (the regulator)