As long as you're checking the starter, be sure to check the cables for corrosion INSIDE the insulation that may be causing resistance. Happened to a Jeep of mine, 1 Battery, 1 starter later I replaced the positive cable and whirrrrrrrr.

 

Yeah, that's what I thought. That's a stop screw, factory set. You're not supposed to mess with it. You're just adding another variable to the equation by "screwing" with it...

Jason

 

Sounds like this truck has had quite a bit of modification.
Possibly with the propane conversion, the throttle position sensor and IAC setups are non standard.

 

factory IAC and throttle position sensors. only real modification was the addition of proapane /w ECU conversion support module. no one works on propane anymore so im on my own.


AS the gas system and AC system was shot (tanks leak, pumps gone, and injectors sezed, compressor shot) I pulled the entire systems, which the truck has not run on for 2++ years and was fine with prior to me starting work. only thing I can think of impacting things here is the removal of the fuel tanks, AC, and injectors is the computers looking for someing on the empty plugs.

Internaly the engine is the same with the exception of high temp heads.

At this point were working 3 problems:

1. hard start when hot only, sounds like low battery. Charging system checks out, starts much better from cold. (indicates battery good, starter & solinod, cables?)

2. poor idle (int. missing) (resulting in messing with stop screw) currently looking at intermittent spark issues on #1,7,8. Wire set wis the next attempted fix. Coil not suspect as its constent on the missing cylenders. #7 & 8 could be cross over but I've done everything I can on seperation, including installing split loom on the wires, and near by metal parts (oil dip etc).

3. hard start cold (intermittent) this is a fuel delivery problem. the propane needs vac to turn on, it seems like it needs a few cranks to open the valves. at this time its vac source is prior to the throttle body. Im considering moving it to where the FPR used to be which is after the throttle body. This is low piority, but may play into the poor idle only if the gas is getting turned off some how. the actuators are all open air so you can put a feeler in (or one is provided) and tell that its open.

Ill check out the TPS and IAC after the missing/hot start problems are dealt with.

Note: timming has been set to 15 degresse rather than 10 as the lable suggests as the propane install lable calls for 15.

I can get that screw back as the rust line is a fairly sharp indicator as to where it was. personaly I think theres some cable strech ther as were talking about 2-4 turns of that screw.

 

Again,......If cables and connections are good,.....slow crank when hot is a starter problem (the bushings).

 

Compression test results.....
1 2 3 4 5 6 7 8 H L %
Dry <120 <115 <120 ~120 <130 <120 <115 ~115 130 115- 88-
Wet <160 ~130 ~150 <150 ~175 <195 ~160 ~170 195 130 66
GAIN 40 15 30 30 45 75 55 55
Retest 5 min soak
~130 ~160 170 180 180 130 72
Retest 60 min soak
170? <140 140 <140 150 150 130 170 170 130 76
Retest (Anomalous results)
125
125 150 130 86
Wet/Dry Difference after 1 hour
GAIN 10 10
LOSS 35 20 10 20 30 30 35



Test completed COLD, throttle closed, all plugs out, 4 compression strokes.

Approx. 5-10 ml of ATF (as suggested some where on this forum) was used in wet testing, cycled open then tested. (excess given opportunity to blow out open SP hole.)

5 min retest was due to tester not zeroing (~35), tests started with it showing 20 then 0 then 35 at 0 pressure. Tests show consistent results.

60 min retest to verify that ATF had time to get into all the places it needed to be.

Looks like #2 is in trouble (low compression wet)..... Looks like this is part(most) of my problem... too bad as I’m not going to be fixing this. Still can’t figure why it started missing after I redid the head gaskets…..unless that heli coil fix on #2 intake rocker did not hold….

Starter …. Compression tests conducted cold due to the known issues here. Cranking from compression testing was enough to a) kill batt or b) heat up starter enough to make no go. Work on this will be completed later.
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Did get it started, burned off all the oil from cylinder tops, still missing, not as bad, was able to turn idle down some more but not to the “factory” position…. Any thoughts on it being a coil problem? I know that the IAC should be tested as suggested.

 

one of the mill wrights here had a thought.... what if the timing chain slipped?

 

Then it wouldn't start and run good when cold.

 

netscanner its not running good cold... it will however start!

my new troubleshooting method: when in doubt read this forum some more....

as netscanner said in another thread slow down and think! what did you change before this started.

1. new plugs, ok, started, ran good. #4 wire came off and it started back fireing, reattached wire, start hard but ran/idled good (40KM, signifigant water loss noted on this trip). Already attributed to starter bushings, indicates no damage to fuel delivery (propane mixer diaphram).

2. fix above caused red vac line to canister to get melted on EGR, fixed with 5/16 line slpice and forma gasket. High idle from low back restored to normal Idle. Now that the formagasket is set could it be pluged off causing low idle? Can is building pressure as when you turn off engine and then pull the vac line the can sucks (could be the line but doubt it).

3. water leak chasing, new heads. water leak fixed. Idle for crap. New parts included:
bolts, gaskets, spark plugs (hotter), cap and rotor, new PCV.... Parts were washed with stale gas (6 years old) upto 2 L was poured over the valley to wash down any crap that wipping up and vacuming could not get. #8 PCV problem very likly as there would be an aboundance of vapours now that working valve installed. relocate seems like a good Idea regardless.

4. exahust leak evident since new heads. Some are suggesting the exhaust gaskets are backwards (metal side in vs out). I happen to know that the pass. side manifold to header dont line up. 1/8 out of allingment. I'll try and get this straingented out as it would likly mess up the O2 reading.

5. inability to start hot, exarbated by repeated attempts at starting trouble shooting all this. Complete agreement with the group on this one that the starter bushings are done. New starter standing by but dont want to subject it to any adbuse unnessisarily.

Other suggestions from the group to check, TPS and IAC, not sure what role the fuel managment system will play with it being on carborated propane but its worth looking at.

Suggestions from co-workers: timming slipped a tooth, MAP/MAF, computer reset.

Ideas from my brian: electronic components on distributior contributing to intermittant miss (no spark)? I know that there is an intermittent miss on #1,7,8. 7&8 crossover could occur but not likly, wires seperated and covered in split loom. near by metal objects also covered ins split loom. Wire set will be in today should deal with #1, and #4 fall off problems. Is it even possible that the coil could do this?

I think I'll stick with the KISS method as the PANIC method is not working and leading down to many what ifs and $$ parts.

Lastly sorry for repeating myself but I know most people only read the last post not the entire thread. hence the recap.

 

Found some one who used to do propane.

His feeling is that the Mixer did indeed take some damage, and to start there, then vac leaks, then the rest.

Eureka!

After the advise above I did some more reading, I even found the service manual for the propane mixer. there are 2 adjustments, power and idle. power adjusts the rich/lean at speed, not overly effective as its dictated by the air draw. Idle on the other hand forces the mixer open at low draw....aka the screw I should be messing with!

This is more than likly the suspect as I did mess with this screw some months ago, it had no effect at the time. at this point it is all the way closed, meaning the engine needs to build air flow(turn over faster) for the mixer to work making starting a supper bitch. Ill be tinkering with this tonight to see where I need to set it to (if it makes any change at all...)

Now why did it change now? I also installed a new low pressure vapor line from the Evaproator to the mixer because the old one was split. This split would have allwed air to be pulled through the hose (and air intake) into the mixer effectivly increasing the apperent air flow, forcing the mixer open and running the engine fine. Now that its sealed I should get better mileage which is why I replaced it.

Hopefully this works! Fingers crossed!

 

all fixed thanks guys.