Truck Help

Joe Gress · #1 07-18-2011, 07:10 PM

My 1988 Dodge Dakota wont start. The engine (carbureted v6), will turn over, and as far as I can tell the engine is getting gas because the fuel is leaking out of the throttle mechanism. The spark plugs, while pretty old and worn looking, seem to all be working correctly and the distributor is running like it should. The engine turns over just fine like its ready to start, but its like its not firing up.

I pulled the starter all the way out to inspect the teeth, and they still have a bit of life left. I've tried jumping it with another car, but nothing changed since the battery (in my truck) has plenty of life and strength to it (bought it in feb).

It ran just fine and started up fine for a week or two before that, no problems whatsoever. It just wouldn't start at all the other day, and hasn't started since.

Help anyone?

carl h. · #2 07-18-2011, 07:32 PM

How are you checking for spark?

MJ5150 · #3 07-18-2011, 07:34 PM

DodgeTalk.com. Seriously. That's where I go for anything about my Ram.

-Mike

hover · #4 07-18-2011, 07:36 PM

crank position sensor. effing chryslers. almost every time. haven't owned a chrysler yet where one of these hasn't gone tits up for exactly what you describe.

Joe Gress · #5 07-18-2011, 07:49 PM

Quote:

Originally Posted by carl h.

How are you checking for spark?

Pulling the wire while its cranking and looking for the arc between the wire and the top of the spark plug.

Quote:

Originally Posted by MJ5150

DodgeTalk.com. Seriously. That's where I go for anything about my Ram.

-Mike

Spent about an hour there this afternoon lol.

Quote:

Originally Posted by hover

crank position sensor. effing chryslers. almost every time. haven't owned a chrysler yet where one of these hasn't gone tits up for exactly what you describe.

Didn't check that, but from what I've been reading for the last two days that my be the place to go. That and the coil in the distributor and the coil itself (which also powers the fuel pump I guess). On dodges of that age I guess its a bit of a problem.

Downunderwonder · #6 07-19-2011, 04:37 AM

Of Dodges I no nought but spark by itself isn't helpful if the timing is off. So the "crank position sensor" could be a good place to look after you have tested the timing to see if it's off.

Coil powers the sparkplugs as a rule. Distibutor sends power from coil to appropriate sparkplug at appropriate time.

Modern ignitions get way over my head, I only know twostroke motorbike and points systems. My Nissan gave up the ghost over a "ignitor" in the ignition. Blowed if I know what that was but the mechanic replaced it and away she went.

fhm555 · #7 07-19-2011, 05:29 AM

If it's turning over the starter is not the problem.

In order for it to run you need spark, fuel/air, and compression.

A quick and dirty way to find out which problem(s) you have is to get a can of starting fluid (ether) and shoot a little straight in the carb throat. If it fires but dies, you have fuel problems. If it fires but backfires or runs rough check timing. If it fails to fire you have spark or compression issues.

If it fails to fire and you have spark, you may not have enough. Most DIY auto parts houses carry an adjustable spark gap tester cheap enough to make it worth buying. Find out what the minimum gap your engine requires, set your gap checker, plug it in to a wire and see what you get. Check all 6 wires. In HV ignitions systems you can have problems from old wires/plugs that still show a spark, but said spark is not strong enough to fire the gas/air mixture.

If you find you have good spark and the starting fluid is not producing at least some popping, check your compression. While PSI is important to a degree, equal pressure between cylinders is also important. If you have excessively low pressure, or more than 10%~15% variation between cylinders, it might be time to have your motor overhauled or replaced. If you suspect compression is the culprit, try filling it with straight 50 weight oil and see if you get any response. If so you most likely need rings and/or valve guides.

If it's fuel problems, good luck. It could be anything from a shot carb/TB, clogged air or fuel passages, stuck float, worn out fuel pump, clogged fuel filter, etc, etc, or it could be a simple adjustment. Like the spark thing, make sure your fuel pump is delivering the volume/pressure it's supposed to and insure your fuel filter is allowing enough volume. After that, get a manual and start trouble shooting your carb.

All that said, a total failure to fire would put me looking at the ignition system for weak or blown parts. I had an old 70 model dodge dart that blew a ballast resistor and it killed it dead. One minute it was running fine, the next minute it would turn over just fine, but wouldn't crank for beans.

**yodedude2** · #8 07-19-2011, 05:58 AM

great troubleshooting post. it doesn't address computer/electronic engine control issues though. the aformentioned crank sensor, for one. we once saw an early 80s vehicle that simply had the computer (i.e., the 'black box') fail.

Joe Gress · #9 07-26-2011, 05:02 PM

So I finally got it running yesterday, ran it for a bit (albeit very badly running), and then it died again. Tried to start again, but it was a no go. So I had enough and towed it to a shop. Fast forward to today when I picked it up. Turns out the carburetor on it actually used to be a throttle body (****ING YAY!!!), and they had used the same wiring and computer for the throttle body injection. The mechanic showed me the throttle advance cable that was pumping gobs of fuel into the carb, and told me that if it floods again (which is what turned out to be most of the problem, but I fixed the electrical stuff), all I had to do was unplug that, and it should start right up.

Long story short it works like an awesome machine of doom once again. The ANTICHRIST PART DUEX!!! is alive and well till the next time.

Thanks for you guy's help and suggestions though! TB is great.

Mike N · #10 07-26-2011, 06:44 PM

88 Should be fuel injected and not carbureted. if you have fuel spraying while cranking the crank position sensor is good. We've seen a ton of coolant temp sensor issues where it's telling the computer it's colder than it really is and that will flood the engine something horrible.

Joe Gress · #11 07-26-2011, 08:11 PM

Quote:

Originally Posted by Mike N

88 Should be fuel injected and not carbureted. if you have fuel spraying while cranking the crank position sensor is good. We've seen a ton of coolant temp sensor issues where it's telling the computer it's colder than it really is and that will flood the engine something horrible.

Yup, and the guy before me, or the owner before him, replaced the throttle body injection with a carburetor. But then again I could have an even older engine than that in there. Do you know how I could look up the engine numbers/codes and maybe where to find them?

Mike N · #12 07-27-2011, 04:37 PM

The only year Chrysler used a carbureted V6 was 1987, after that they were EFI.

Someone did you a dis-service by yanking the throttle body injection.... they are light years ahead in economy and performance versus the junk two barrel Holley that was previously used.