3fe insight?

This site may earn a commission from merchant affiliate
links, including eBay, Amazon, Skimlinks, and others.

Smplybttr

Smplybttr

10 Year 15 Year
Joined
Jun 21, 2010
Threads
45
Messages
399
Location
Cary, NC
First of all, I'd like to thank Johnny for spending a couple of hours in the cold wind helping me troubleshoot my truck yesterday.

Here's what we did/ figured out:

Sprayed brake cleaner to test for vacuum leaks and could find none.

We pulled plugs and wires and found that #2 doesn't seem to be firing. We got spark, but when we pulled the wire, the engine didn't waver.

Ohm tested #1 and #2 injectors and got 14.2 Manual says that it should register 13.8

Checked compression on three cylinders. Book says 149 psi. We got 70, 30, and 0 (zero was #2). Although we used two different compression gauges, their efficacy was in question.

Despite the miss and the compression issue, the truck has plenty of power. I have no issues driving 65mph. However, it likes to stall when coming to a stop and has a rough idle. It didn't make sense to either of us that the truck runs well at higher rpm and has such little recorded compression.

WTF is the question. Anybody have any answers?
 
Terry, no problem man, it was a good time! Sorry we couldn't identify the issue, but we were able to narrow it down a little more.

Also checked the resistance for the cold start injector, which measured out between 2 and 4 ohms, I think it was 3.2. Either way, that measured within spec.

When I took the #2 spark plug wire off while running, I got zapped through the wire. Took the #2 wire off of Moonshine to test but it didn't make a difference.

We pulled some of the spark plugs and found what looked to be a nice, even burn. #2 plug looked exactly like #1 and #3.

We drove around in it yesterday and while the miss is there, it seems to run relatively well! Not way low on power, difficult to accelerate, etc.

Not sure if my compression gauge is working properly, so I'll try to remember to measure compression on Moonshine later today.

I think a next step would be to have someone with a known good compression gauge measure your motor. Based on that result, maybe a leak down test.

Couple of questions Ramon and I came up with last night:

1. When you replaced the head gasket, I know you said you had the head worked over. Did you replace some or all valves? Did you deck / shave the head / check to make sure it was flat and true?
2. Did you re-torque the head bolts after 500 miles of driving or so?
3. Were the valves re-adjusted when the head was re-torqued?

Hopefully someone with more 3FE knowledge will chime in with more suggestions. We'll get to the bottom of this!
 
The head was worked by T. Hoff and I assume they did all that was necessary to bring it up to spec, including repainting it. The exhaust valves and seats were replaced, but the intake valves were not.

I did not re-torque the head bolts, nor did I re-adjust the valves. I didn't realize that was necessary.

It is possible that the #2 wire is damaged and not sending the right signal. If anyone knows how to test it, that information would be great to have. I wonder if I bought an extra injector and plugged it into the clip, would I be able to test the wire that way? I don't think it's possible to remove that injector without removing the EFI completely.

Thanks again,
Terry
 
I would start with a re-torque of head bolts and valve adjustment. If it makes any sense if the valve's are any where out of whack on that one cylinder you are not going to get compression because both are allowing compression to pass thru. When I redid the head work on the 55 I found this out, go through each one and check them hot. Much easier with 2 people and relatively easy on the 2F, not sure how throttle body may play a part in adjustment. For the signal wire...couldn't you just swap for another cylinder and see how that reacts?
 
as a 3fe owner I am paying attention......and i have a compression tester i can bring to the meet&greet...
maybe add a little oil to #2 (or all) ...prior to testing to see if it is the rings
 
Well, what's the conclusion? Did the valve adjustment clear up all troubles or no? I know it was idling high the other day...
 
Overall, she's running much better and quieter. There is still a miss of some sort when in gear and sitting still. It's intermittent, so I'm not sure what it is. Also, she just started making a noise that sounds like I'm running over rumble strips. The first time it happened, I thought it was a flat tire, but they were fine. It doesn't shimmy or pull and the noise seems to happen at about 50-55 and cruising. If I let off of the gas or go harder on it, the sound goes away until it settles into cruising speed again. I guess it's in the drive train. There's always something...

Terry
 
You must log in or register to reply here.

Share this page

Back
Top Bottom