The new life of the formula fastback

[NoMad]

Didn't change the coil, just the ICM

So fuel pressure testing....

Initially goes to almost 60 psi! Then settles down to near 45 psi. Snapping the throttle open in neutral results in a spike to 57 psi then back to 45. Holds 45 till red line without issues when cold.

Left it running and repeated tests as the motor warmed. Once hot a pull toward redline would drop the pressure to 20 psi for a moment then rebound. As it continued to get hotter it wouldn't even reach redline as the pressure would drop to 20-30 and stay there. I started to see some smoke so I let off and shut it down and saw the muffler and the CAT were both red!

As I left for work (driving the truck) the fuel pressure gauge was reading 0 psi this time. It was holding before it was warm. Might mean an injector is sticking open causing the FP drop and a super rich cylinder which could ne causing the cat to work extra hard and thus the EGT being so high but only CAT and back as the manifolds were not getting red.

So I am asking:

Is the pressure is supposed to spike like that on acceleration?

Is the high starting pressure an indication of a bad FPR?

I am assuming my pump is failing and heat is exasperating the situation. Or the above mentioned injector issue.

Also assuming the red muffler and cat is a result of high EGT due to the lean condition when the fuel can't keep up, or tue rich cylinder causing excesive combustion in the CAT and this high EGT from the CAT back.

Thoughts?

[Fierofool]

Fuel pressure should only drop to about 36-38 on a good system.  Prime pressure should be somewhere around 42 or higher.  Normal idling pressure is about 40 on a good system. 

If the problem was lean a/f, the exhaust manifolds would glow.  Retarded timing can give the same result.  Sounds like it's dumping fuel into the exhaust.  I didn't realize it still had the catalytic converter on it.  I thought it had been removed before we got it. 

You might get a little spike at the start but the regulator should release the pressure to the tank return line.  Both your high and low readings are far out of range for what I understand as normal. 

[GTRS Fiero]

It reads as if something is blocking the fuel lines.  If so, the fuel pump will eventually burn out.

I would check the vacuum line on the FPR first.  It almost sems as if the issue is there.  The fuel pump and FPR do not know about the throttle, RPM, or temp.  If there is a leak or blockage in that area, it could cause the problems you're experiencing.

[NoMad]

So I finally got a few minites today to work on the car.

First, it turns out the car has an adjustable fuel pressure regulator and some quick adjustments had the pressure working right. I also ran the troubleshoot on the fuel line and the return was clear. I was able to perform a run up and some fast temp checks. The reduced pressure seems to have cleared up the hesitation and I am not seeing the cat and back afterburner that got the cat and muffler so hot. I wanted to test further but while I was running the motor up near red line to look for the hesitation and pressure drop I saw atomized liquid spray on the belt side. I feared I had failed to tighten the return line so I shut it down and looked. Fuel lines were fine so I fired it up and saw coolant coming from the Thermostat cap.

Went to try and get another but the stores near by had none in stock so I came home to a now cooled motor to take a look. Found that the Thermostat had gone from normally seated to the small arms being bent in on one side and the thermostat dislodged. Not sure how that happened but it appears to have been during the run ups.

Since thw coolant still looks so muddy I figured tomorrow starts a flush. I ordered the evaporust cooling system flush as well as new caps for the rad and thermostat as well as a slant superstat. Amazon will be delivering it all over the next two days so I should habe it all back to clean and usable so I can finish trouble shooting.

Best guess is that the increased fuel pressure is the culprit behind the poor economy, the hesitation, etc. Likely from a sticking injector.

Seems strange to do so much just to swap the motor but I want it running right till then and also to be good to go for the new owner of this engine.

[GTRS Fiero]

The adjustable FPR is a PITA, and unnecessary on that engine.

The thermostat usually gets bent if not seated correctly when the cap is installed.  There should not be enough pressure to bend the thermostat.

[mweldon]

Good job, way to stick with it..

[Fierofool]

We aren't 100% knowledgeable of what Dave Belville did to that engine when he built it.  Based on his word and others who have some knowledge of the engine makes us believe it was bored .060 and got a mild cam.  He certainly replaced the stock injectors.  When MikeMac pulled them to install new ones, he ordered the same injector number.  They weren't Fiero and they weren't CamaroBird Rochesters.  Dave installed the adjustable regulator for some reason if it was there when we sold it. 

[GTRS Fiero]

.060  bore on a 3.1?

[Fierofool]

He said he chose that engine from a FWD van because the starter was already on the correct side and the cylinder walls were thicker than the engines used in the cars.  The 3.4 had not yet been introduced. 

[NoMad]

Well I did a test drive last night and it took a different turn. Started to feel like it was running on 5 cylinders, then when hot the surging came back. I grabbed a new set of NGK V power copper plugs to replace the ones in the car. I had held off due to thinking the plugs had been changed during the clubs work on the car. From what I found today I am thinking the plugs were purchased but not installed. This is supported by the plugs that were still new in box in the trunk when I bought the car.

So the front bank were rusted in place so much that I couldn't even get the plug socket down past the insulator. It was a screwdrivers as picks and PB blaster kind of chore. Took me the better part of an hour to get them cleaned out enough to get the socket "on" what was left of the plugs. There really wasn't enough of the material left to be called a nut. Had to side load the socket against the head to get them moving. Was not a pretty sight.

So the view only got worse after cleaning up the ports and checking compression. Comps were roughly as follows:
125 - 125 - 95! - 150 -150 - 160. So not good to say the least. Cylinder 4 looks dead in the water. Went to do an oil test to confirm rings or valves and had my compression tester schradder valve die. A trip to Advanced later... I was back and the motor was so cold now nothing was showing good comp. All cylinders were showing around 90 with 4 showing 32! Oil in and #4 reads 89/90. Rings it is. On a whim I decided to try the Engine Restorer after seeing good indepe dent testing results from unpaid third parties. So I drained off some of the oil I had just put in and added a can. Redid the timing an was ready to try her out.

Test drive was about 35 miles and it seemed to be running on all 6 cylinders again and smoothed out a nit by mile 6. Felt good with no surging. Mile 24 the surging started up. Got it back to home before the surging got too bad and will warm and compression check in the AM. The restorer is supposed to take some time and heay cycles to really worm it's magic but I plan to take an initial reading on a few cylinders just to see if there was any early effect.

Also did the testing on my temp gauge circuit. Was Not seeing signal from plug to dash so I was worried there were larger issues at hand. After mucj testing and cursing I pulled back the wire protector to find the the new plug end was added long ago by the twist them together and add e-tape method. Broke that down and checked again. Good signal all the way to the dash. So a couple heat shrink butt-splices later and the addition of a chunk of #2 double wall glue filled heatshrink to hold all of it super secure, and I was able to add a new terminal end from Rodney and check again. Good signal to dash. Passes dummy light and curent tests. Zerp movement in the gauge. So a new temp gauge will have to be sorted asap.

So tomorrow will see a compression balance quick check and I will likely drop the tank as the last culprit on the list for the surging is likely a failing fuel pump. Since thos motor or the LQ1 will both need good fuel flow I feel okay making that purchase even of the compression doesn't return with the snake oil.

If the motor is dead I will need to really kick the LQ1 train into gear and fast.

[GTRS Fiero]

Interesting.

I thought that Fiero was supposed to be rust-free.  I can't recall ever seeing installed plugs in the condition you described.

[Fierofool]

I don't recall if we ever replaced the plugs, either.  If they were in the trunk, it was certainly planned but may have gotten sidetracked by other things, not necessarily related to that car.  MikeMac did a lot of work while at Northlake when he had the time.  Could have been on his list but business interrupted. 

We have installed 2 fuel pumps into the car.  You may have a warranty receipt in any papers we gave you. 

I wouldn't have expected it to have low compression by the way it ran.  It seemed to idle well and had plenty of power.  I believe I replaced the cap and rotor early on when I had it here at the house and was trying to get it running.  I don't remember if I replaced the plug wires, though.  We did pull plugs 1, 3, & 5 to check them when it started running badly.  That's when we discovered the plugged injectors. 

[TopNotch]

If you put oil in a cylinder, and the compression is still low, it's either the valves or a leaking head gasket.

[NoMad]

Ya, oil brought them up a bit.

So I am officially blown away! I only have about 30 miles since adding the engine restorer and after a 20 minute warm-up idle all the compression is within 8 psi of each other! It is still slow to build on. A few cylinders but since it should take till 200 miles to be worked in I am really impressed. All the numbers were different than yesterday but all uniform so I would put that down to heat being closer to equal as I didn't have the long cool down while I fought the front plugs.

Short test drive showed good driving and some stalling when letting the revs drop fast with the clutch in. Also pointing to the Fuel pump failing. Will grab a new pump and strainer from NAPA or one of the chains and drop the tank tonight after work and do the coolant flush at the same time.

[Fierofool]

Did you check your paperwork for a pump warranty?  I think Mike may have gotten it at NAPA.