Okay guys , how's it going...?

Our buddy Jose has a 1994 Dodge Ram 1500, with a 3.9L V6 gas motor.....

Remember, I asked nice (ntbb), it has an intermitant (all of the last two years) problem and I am at an end with it....starting issues, backfiring issues, surging issues.....

Tried talking him into a GM, but he is stuck on Dodge....

Does anybody know this trucks well, or have a site we can go for some good info.... had him take it to the dealership to diagnose with their computer, didn't even have patch cords anymore.....

I don't remember the last time we took a vehicle to a garage for a repair......this was for diagnostics and they started throwing pieces at it, $620.00 before we stopped them.

Thanks ahead of time,
jim&jeff.

Moved this to Any Other Vehicles for ya :p:

I think I know the problem, It's a freakin' DODGE

No seriously tho, Engine fires are known to happen

No seriously tho, Engine fires are known to happen

Think it would be suspicious if its a diesel fire?????:eek:

tell him to check the coil, and the electronic thing inside the distributor. my friend had a 98 dodge 5.2V8 that would die outa nowhere and backfire. his problem was the thing inside the distributor. he also figured it was the fuel pump going bad.

Bad injectors.

Been so long since I worked on a gasser, and most of the gassers I worked on were old.
Sounds like ignition probs to me. It's probably to new to have a mechanical advance inside the distributor, but the symptoms sound like a distributor with sticky or worn advance arms. Leads me to believe that the engine speed sensor is dirty or has failed. (No I don't know where it is on that vehicle, flywheel? distributor? crank pulley?) Typically when they fail they take out a few other sensors as well, which leads to catalytic converter failure. Cat converters tend to plug up on engines that run poorly for a long time.
Whenever I work on gas engines, the first thing I suspect is dist cap, plugs, and wires. people usually don't keep up on these. Even if it's electronic ignition, pull the plugs, clean, close the gap just a hair, if that makes a diff, it's probably ignition probs. (I always run my plugs a little less gap than recommended).
Like I said, old vehicle was my thing, but next suspect would be the carburetor. I guessing this is throttle body injection. If so, there are sensors in there, other than that I'm not to familiar with throttle bodys

What's sad is that the shops charge so much for the diagnosis. But they are usually on the right track. When a sensor fails, the engine doesn't know how to run right, causing other sensors to fail. Sensors aren't cheap, but they are usually the prob. Too bad that $600 wasn't spent on a code reader.
What usually happens on a rig that has been running bad for a while is a reader will pop a codes out, you fix those, then the reader will pop the "next in line" codes out, fix those, and so on till all is well.

Thanks guys, here's a list of what has been done so far...... not including body restoration, paint and stereo system.....

rebuilt heads, with all new valves

new camshaft with timing chain and gears

new oxygen sensor

cat removed and muffler changed

fuel tank dropped and cleaned, filters in tank removed and pump verified (38psi)

new plugs, wires, cap and rotor.....have two different pick up coils, one seems better than the other

When running, and plug wires are removed, equal miss for all 6 cyl.....
the same goes for injectors, when unplugged, equal miss on all 6 cyl.

Have erased ecm multiple times and slowly replaced sensors and pieces..... the last code coming up now is a/c relay (no a/c on this truck).

The dealer that we took truck to, never had the reader for this truck, so had to bring one in.... told them to diagnose problem and not repair..... they started throwing parts at it, and when we stopped them, truck would not even run..... finally cost just the price of diagnostic and we left with the new oxygen sensor for free. They also said pick up coil, so we installed one. They tested the primary coil twice that we know of (once when I was there), although just a spark strength test.

This truck has now a total of 250km in the last 2 1/2 years it has been around ( we want to do conversion to 6.9L IHI auto, owner doesn't).

Thanks for replies, if my added helps, let us know......jim.

sounds like the ECU is pissed off. especially if its throwing a/c codes at you when theres nothing there!

The SBEC module will throw A/C and cruise control codes even if they aren't there. So long as it isn't turning the check engine light on I wouldn't worry to much about it. The ignition coils are probably the number 1 failure on any of the older DODGE's followed closely by the crank position sensor. Also those engines are known for blowing out the intake plenum gasket if it doesn't have the new steel one in it which will cause it to burn oil as it will be sucking oil straight out of the lifter valley when it's running and this will foul out the plugs BAD. ALso make sure it has GOOD 8 MM plug wires and CHAMPION plugs in it. I have fixed ALOT of DODGES by doing just these 2 items. Also it wouldn't hurt to hook up the fuel pressure guage and watch it while driving, I've seen alot of em hold good pressure at idle but fall off under a load(should be around 32 at idle and 36-39 at WOT).

The SBEC module will throw A/C and cruise control codes even if they aren't there. So long as it isn't turning the check engine light on I wouldn't worry to much about it. The ignition coils are probably the number 1 failure on any of the older DODGE's followed closely by the crank position sensor. Also those engines are known for blowing out the intake plenum gasket if it doesn't have the new steel one in it which will cause it to burn oil as it will be sucking oil straight out of the lifter valley when it's running and this will foul out the plugs BAD. ALso make sure it has GOOD 8 MM plug wires and CHAMPION plugs in it. I have fixed ALOT of DODGES by doing just these 2 items. Also it wouldn't hurt to hook up the fuel pressure guage and watch it while driving, I've seen alot of em hold good pressure at idle but fall off under a load(should be around 32 at idle and 36-39 at WOT).

x2 about the crank position sensor, no personal experience but have heard about this happening numerous times.

The thing in the distributor that 4320 is talking about (I think)is the ignition module or ignition control module or modulator or a half a dozen other similar names. I don't think that would be the problem 'cause that usually causes a sudden no start condition. Nothing to do with how it runs.

I still think engine fires happen very suddenly on well insured Dodges

the thing i mean is kinda the electronic version of points and condencer.

the thing i mean is kinda the electronic version of points and condencer.

94 DODGE will have a true MPI system that uses a crank sensor in the bellhousing that reads the flywheel for when to fire the ignition and injectors and has a cam sensor in the distributor that does nothing more then tell it when #1 is at TDC. Many of the early DODGE's would stay running if you unplugged the cam sensor after the engine was running. Coils on these are engines are VERY failure prone though as they are VERY high voltage and they weren't insulated very well up until about 96. The PCM controls everything about the engine in that truck, but if it can't read cam and crank correctly it will go haywire.

Have not had chance to try any of your suggestions yet, (no engine fire) but we are starting to run with it everyday to see what it does......

O yah, got the okay to transplant the 6.9L/C6 combo into it if doesn't straighten out....

Thanks for suggestions, we'll get back to you with updates....

Have not had chance to try any of your suggestions yet, (no engine fire) but we are starting to run with it everyday to see what it does......

O yah, got the okay to transplant the 6.9L/C6 combo into it if doesn't straighten out....

Thanks for suggestions, we'll get back to you with updates....

If there is no spark it is most likely the coil, or crank sensor. Cam sensors rarely fail, but it does happen occasionally. Have you done the key on key off 3 times and pulled the codes?

The no engine fire was not a reference to no spark..... just that we haven't burnt it down yet....LOL.

Yes we've pulled the codes about 30 times already, last one was just the a/c (12 & 55 also), been running it a little, not too bad for now....

The crankshaft position sensor is new. When at dealer, one of the first things they verified was the coil (front pass side of motor). Last time it gave me problems, pulled coil wire off and there was only minimal spark..... immediately pulled #2 plug wire and had orange colored spark (not real hot blue/white color).

If Jose wants to throw more money at it I'll suggest the coil (labour is cheap $0.00 for him).

I'll see what the kid says and give you guys news.......thanks for your interest and suggestions...

Another free thing to do is swap the ASD relay for another relay and see if that helps. The ASD relay powers the igniton coil in that system and the points in them can burn over time. Also the ignition switches were problematic on earlier DODGES, check to see if it has had the recall done to it yet.

I had a 91 Dakota with the 3.9 v6 and it would suddenly die and not start. No spark at all. Then after sitting awhile, it would fire right off. After several trips to a few different mechanics/dealers i finally figured it out. The positive lead to the battery had rubbed through on the frame, and would sporatically ground out. electrical tape and it never happened again.
doesn't sound like what you have goin on, but something to look at.

Another thing to look at would be a DURAMAX.

I had a 91 Dakota with the 3.9 v6 and it would suddenly die and not start. No spark at all. Then after sitting awhile, it would fire right off. After several trips to a few different mechanics/dealers i finally figured it out. The positive lead to the battery had rubbed through on the frame, and would sporatically ground out. electrical tape and it never happened again.
doesn't sound like what you have goin on, but something to look at.

Another thing to look at would be a DURAMAX.


We can buy a lot of fuel for the price of your duramax.......:D

Bad ground cable/wire?

So far the best thing I have read to do is the engine fire thing.