HI there I could use some suggestions please!


I have a 94 Dakota Sport with the V8. Yesterday I took it on a 60+ drive with my trailer to drop a load of styrofoam. On the way back I stopped at Shell to get gas. About 15 miles later the truck started chugging like it was going to stall. I slowed down and it started back firing. I was 45 miles from home. I stopped and got some dry gas and limped home. The next day it had trouble starting. It cranks for a little while before it will turn over. Here are the symptoms...

• Backfiring under load
• Wants to stall when idling and going up hills
• Rough idle
• Hard starting

A little about the truck. It sat for a few years hardly being used. It is a 1994 with only 80,000 miles on it. I got it in November and since have replaced...

• Spark plugs & wires
• Distributor cap & rotor
• Brakes & Tires
• Oil Sending Unit
• Thermostat
• Brake Lines
• Part of the Fuel Line (it leaked when I purchased it)
• Other things I'm sure I just can't remember

I've read the FAQs and here is what I've tried so far...

• I took the tape off and checked the Notorious Splice Area. Everything looked good.
• Found the PCV valve was broken so I fixed that.
• I checked the codes and came up with 55.
• I had someone turn the key and I listened for the fuel pump running.
• Switched out the Fuel Pump Relay to make sure it was working.

Here are my questions:

• When the key turns on should the fuel pump continuously run? I can hear it for like 5 seconds then it stops. Is that normal?
• Is the only test I can run to check the fuel pump using a fuel pressure tester? I'm pretty new at this so I don't have one of those. Autozone carries one for like $25 here. Would that work for me?
• I want to find out if it is the fuel pump before I remove the entire bed. Michigan winters are tough so it is really rusted. Has anyone removed the bed on their 94 Sport. Is it pretty simple?
• My dad thinks it could be just water in the gas from the other gas station. Could that be and if so shouldn't the dry gas have taken care of it?
• I'm thinking of cleaning the IAC as well. Would that be a good idea?
• Anything else you guys can think of?

Thank so much for your help!

BTW, the FAQ on the heater blower was spot on. Saved me a ton of time/money.

 

Ya I would say start with fuel pressure and volume tests. The tester you provided is for carbureted engines. This one will work. http://www.harborfreight.com/fuel-in...ter-92699.html

Typicality for backfiring it is a timing issue. Make sure the TDC on #1 cly and the #1 position on the distributor are correct. The picture in the FAQ will help with that.

 

Thanks so much for your reply!

I got the tester. Now please forgive the newbie; according the to book you test it with the engine running. But, online it said to test with just the ignition on. Which is it? I tested both ways....

Ignition on only = 15
Running = 40 (it jumps all over at first then lands on 40)

I also checked the vacuum hoses to the fuel pressure regulator and they are solid and not burnt or anything.

Also, it isn't backfiring anymore. Now it just runs really rough and eventually dies. Leave it for a few minutes and it cranks a little then eventually takes off.

Ideas?

Thanks again!

 

Do you have oil consumption issues? That coupled with lack of power on hills/under load could point to a bad plenum gasket/pan.

https://dodgeforum.com/forum/2nd-gen...um-thread.html
^ great plenum info thread

Also, try using some electronics cleaner spray on the throttle position sensor. They can cause idling issues when they're dirty/seized up.

 

It doesn't consume much oil but it does have a weird problem. Quite often the oil pressure will just drop and the oil light comes on. It has done that since I bought it. It usually happens when I'm idling. I replaced the oil pump and oil sending unit with no luck. Could this mean the bad plenum gasket/pan?

I'll clean the throttle position sensor tomorrow.

Thanks again!

 

The oil pressure sensors are notorious for that problem. I know you bought a new one but many others will also tell you that its been known to buy several new ones and them too be bad out of the box. Best thing to do is get a manual gauge and check the pressure to make sure the oil pressure is ok.

 

My oil pressure gauge was steady at idle, but would drop real low under load. Plenum problem fixed that.

My truck was burning more than a qt or oil per tank of gas, but there was absolutely no gasket left. If yours is less shot, it might consume less oil than mine did.

 

I'll check the plenum today after work.

Thanks!!

 

Hi here is an update: I cleaned the throttle body (it was really gunked up), looked inside at the plenum and didn't see any oil pooling, cleaned the tps, replaced the pcv valve and checked the hoses. I found a torn hose and replaced it. I also checked the distributor for any signs of burning etc. and it all looked good.

So I put it all back together and it started right up! I took it on a test drive and after 15 miles it started acting up again. It was running really rough on idle but seemed almost ok when I was driving normal speeds. I stopped at a stop sign and so did it. I tried to start it, waited 5, 10 minutes tried again nothing! I checked all the hoses and wires and still wouldn't start. It cranked but wouldn't start. I ended up being towed back home!! Dang. This is my work truck and I have a job Friday. Yikes! Any other things I could try?

Thanks again.

 

Well now that it is not running what is your fuel pressure?