help me diagnose this:

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Combat Chuck

Combat Chuck

10 Year 15 Year
Joined
Sep 16, 2008
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Location
Freensville
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www.poolpartydeathmachine.com
My truck's developed a peculiar habit, and I need a second opinion.
Since getting it back from the shop with the new timing chain, I'm experiencing a loss of power uphill, in third gear uniquely, upwards of 3000 RPMS. It will hold true to anything below that, but over 3000, I can just feel the pedal sink to the floor, and then the revs just drop, and I pick up some pinging and backfiring.

It's not surging like my plugs are tired, it feels like fuel starvation. I've changed the fuel filter since the first occurance of this, which was pretty plugged, bit I still have this loss of power, just not as abruptly. I'm growing to suspect my POS Autozone fuel pump is finally caling it a day, and causing fuel starvation, but I was wondering if anyone had a second opinion, or experience here.

I don't encounter this problem uphill in second, and I don't encounter it flat at 55+ in fourth and fifth, or even up slight grades in those speeds. on a flat road, my truck will hold 3500+ in third no problem, which makes me think there's an issue of fuel delivery.
 
thats an interesting one....
i dont have any first hand experience with this, but it sounds like you might be on the right track.

yours is carbed right? maybe check the jets and floats in the carb too???


edit-- another thing you might try is run up the hill in third like you say, when it starts to die out pretty good, kill the ignition and coast over to the side of the road, then get out and pull some plugs. see if they indicate a lean condition???
 
I did just chase down a vac leak, that might've been a contributing factor.

I just took The Mule up to Mount Saint Helena, and she pulled well the entire time up, no major issues.

I think it was a combination of the vac leak, and the very plugged fuel filter.

I'm still suspicious of the FP, but it was my only option for a Sunday evening driveway fix.
 
Do you just have a generic in-line fuel pump? If so you should check your fuel pickup in the tank. Mine was completely stopped up and causing weak fuel pressure. Since you had some trash in your filter it may be worth checking.
 
Lowe Toyota said:
Do you just have a generic in-line fuel pump? If so you should check your fuel pickup in the tank. Mine was completely stopped up and causing weak fuel pressure. Since you had some trash in your filter it may be worth checking.
Click to expand...

I think that sounds like a good idea.

I need to drop the tank and clean it this winter break anyway.
Anybody recommend any solvents for cleaning a tank out?
 
To me that sounds like the timing is off, either cam or ignition. I had the same thing about 10 years ago after I did the timing chain and my ignition timing was a tooth off. Might check into that as well...
 
Combat Chuck said:
I think that sounds like a good idea.

I need to drop the tank and clean it this winter break anyway.
Anybody recommend any solvents for cleaning a tank out?
Click to expand...

Por15 makes a kit that I have heard good things about. I opted to let someone do mine since I got such a good deal. Most of the research I did before suggests using something to etch the tank and then coating it. I'd check your rust content though. That's going to be the deciding factor.
 
Combat Chuck said:
I need to drop the tank and clean it this winter break anyway.

Anybody recommend any solvents for cleaning a tank out?
Click to expand...

I've used the kit from POR, and the kit from Eastwood, on a pair of old tractors (1939 and 1946). Both kits did the job.
 
So, this morning on my way to the gym, I smelled gas strongly, and checked around, it wasn't coming from the tank and lines, but from the hood. I noticed fuel pooling on the AC pump, and watched my fuel pump for a bit before noticing fuel leaking from the weep hole. It was shot.

So, I picked up a Bosch unit for it, which was about twice as built as the Autozone POS, threw it in, and it starts better, accelerates smoother and offers more power, but now I've got a small backfire downhill in a lower gear. I warm the engine up to a good temp before I go anywhere, so i know it's not the cold-start backfire, and it's not the giant KABOOM I would get last year, it's a chatter of smaller backfires.

Here is my suspicion, and please comment on it if you have a better/similar idea:
I think my AAP diaphragm is toast, as this engine has always backfired a bit downhill, but since the Autozone pump was functional only enough, there wasn't enough guel present in the carb for it to leak through the vacuum line, however, with this fresh new pump, it's flowing fine, and enough fuel is dripping from the AAP diaphragm to cause a machine-gun backfire issue.
What say 'Mud?

Also, Crazy, report this to the man upstairs: I got a whole eight months of daily driving out of the AZ pump, that has to be a new record for length of lifespan!
Tell the boss I expect a plaque. :flipoff2:
 
Last edited:
crumbo said:
Timing
Click to expand...

this seems to be the overwhelming consensus.
Time to wave my timing light at it menacingly when I get home from work this morning.

The numbers I have say 5(w/Adv.) and 12(w/o Avd.) TDC for an early 22R, any dissenters?
 
So, just to clarify, we're talking about ignition timing, correct, not rotating assembly timing?

If so, I have no FSM or Chilton's guide on hand, so does anybody have the procedure for adjusting my ignition timing?
I'm talking about a first-generation 22r, tall deck, short head, ign. coil with round plugs.
Much obliged.
 
Looks like my ignition timing was off by 3 degrees.
Seems to run good now, but I'll know for sure tonight.
 
I have been tuning ig. timing by ear for almost 20 years. Its fairly easy to tune, if anything from what you desribe, advance the dizzy 2 degrees just for a start, thats not to much for the engine to get hot if in fact its currently set where it needs to be.
Grab you a 10 mill wrench and check back in:D
Combat Chuck said:
So, just to clarify, we're talking about ignition timing, correct, not rotating assembly timing?

If so, I have no FSM or Chilton's guide on hand, so does anybody have the procedure for adjusting my ignition timing?
I'm talking about a first-generation 22r, tall deck, short head, ign. coil with round plugs.
Much obliged.
Click to expand...
 
the backfiring has cleared up, and I have two working hypotheses:

1. Something in the fuel.
The afterfire was its strongest between the fill up immediately following the new pump, and faded out following the fill-ups between now and then. So, it seems likely that a contaminant in the fuel may have induced problems.

2. The potential for a cracked plug wire.
This truck's had it's head off recently, and I've changed the plugs a couple times with the same wires, and I wouldn't ignore the potential for fatigue or cracking. All it would take is a minute shift in the angles of the wires to cause trouble with even a small crack, and it would be as intermittent as anything because of this. I have new plugs and wires on my passenger seat for tomorrow.
 
While changing the wires you may want to check the inside of the distributor cap carbon cracks can join the wire towers causing misfires. Also a weak igniter could cause somewhat of a missfire at speeds above 45 MPH. I am assuming here that your timing advance mechanism in the distributor is working.
 
Now I'm chasing a vacuum leak.
Joy of joys, this damn truck's the gift that keeps on giving.
 
I am sure you know the trick of spraying carb cleaner around the suspected areas. The cleaner will seal the leak temporarily and will smooth the truck idling.
 
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