94 1500 318

94 318 rough start/ idle/ fuel cutting out

Hello all,

I am new to RF, new to Dodge, new to trucks..but my enthusiasm has only begun.

I bought the truck off of craigsist for 900$ cash. It has 91k miles on it (motor looked like it; no compression test was done) It has the usual 20 year old rust, an exhaust leak in the inter med. pipe, and a clean intake keggar. It drove great when I test drove it, and all the way home too.

This was to be my daily driver and possibly hauler (has towing lights/package already installed) at work. My usual car treatment began. Oil change, seafoam in the vacuum( only 1/3 can), full tank of gas, repaired small vac leak, changed spark plugs(look for issues mostly), and seafoam in the gas tank as well. Looked at the IAC (clean as a whistle), throttle body was too.

Then the last 211 miles have been treacherous. A rough idle began, missfires began (no fouling though), surging when taking off, not steady power flow. I immediately repaired the exhaust leak. She ran a touch better, but as I continued to drive her: she got worse. The catalytic converter began to rattle, suspect to a clog. IR Temperature readings indicated a clog, so I replaced with a magnaflow cat and new o2 sensor (******** never used anti-seize). About 1/8th of gas left in the tank, she left me high and dry in an intersection when she stalled out at a complete stop. It would not restart. I waited about half hour (40 deg outside) she fired up.. but seemed like she wanted to stall at any point when i slow down to stop.

Popped the hood, wouldn't start. The search began, as I checked spark.. it was there. Checked air at the throttle body, it had massive vacuum. Then I decided to spray a ton of starter fluid in the intake..she almost wanted to fire up completely!

Took my HVAC pressure reader, hooked it up to the fuel rail, when cranking it read only a spike to about 7psi...

Tomorrow AM, I am installing my new fuel pump and plan to lift the bed.

I think seafoam cleaning it of buildup clogged the cat, which caused the rough idle, to already weak fuel pump (guess the truck wasnt driven much in the last 20 years with 91k.) I hoping tomorrow she purr's after the new fuel pump..

Anyone have any other thoughts on my situation? I've never has this issue.. thought I got a needle in the haystack by getting a greak deal on 91k miles.

Bump.

Installed fuel pump, got 40 lbs of pressure at the rails. But she still won't start, I notice I am not getting spark to the coil pack. I bought a new coil pack, and STILL no spark. Needless to say, checked the fuses and the ignition coil pack 30amp fuse was blown. Popped a new one in and before I even rolled over the motor she blew the new fuse.

I am not electrically inclined but imagine that I bumped a ground when installing the fuel pump or catalytic converter or coil pack.

Someone set me in the right direction! I've got a multI meter in hand, but don't know what to follow.

Update again:

Had her towed to the shop. I found the ground somewhere with the Auto Shutoff Relay, and specifically the wires to the Ign. Coil Pack, but couldn't find the bugger.

Needless to say...she left me stranded.

New parts:
-o2
-spark plugs
-ign coil pack
-fuel pump
-catalytic converter
-inter med pipe
-iac sensor (cleaned it up along with TB)

I need help! Can someone put in their 2cents about the situation? I am so lost at the moment..

The shop called today and said they found the grounds, fixed em up, and will start right up and run. But it runs so rough still..never ran rough before I seafoamed it.

But once I drive it, its almost like a plugged injectors? It'll feel like it gets power at 2500RPM's and then a moment later it feels like it lost power all while still holding the same RPM's when driving. The new plugs are burnt white..meaning my motor is running hot, meaning its not giving enough fuel? Or that's my guess atleast..

If I let off the gas and let the RPM's go back down, it'll dip to almost 0 RPM's while driving! Normally to me that is a sign of a bad fuel pump... but I JUST replaced that and get 35psi of pressure on the fuel rail...no bouncing or anything.

May sound stupid, but you haven't mentioned changing the fuel filter.


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You should have around 49 psi of pressure, not 30s. I'd be willing to bet something is in the lines.

you can't change the fuel filter on a 2nd gen. they are build into the pump. and since he replaed the pump, he has a new filter.

I knew it might sound stupid. Lol


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I didn't make a mention of it. I didn't want to be "that guy".

Thanks for taking the fall for me, Lauren.

LaurenMagnum360 said:

you can't change the fuel filter on a 2nd gen. they are build into the pump. and since he replaed the pump, he has a new filter.

Click to expand...

Straight up this is wrong, you can change just the reg/filter look in the parts books people its in there.

94-96 part numbers are. Page 452 in the 96 parts book( I just used this for reference).
4864 849 1994-95
4798 825 1996

dodge dude94 said:

You should have around 49 psi of pressure, not 30s. I'd be willing to bet something is in the lines.

Click to expand...

His sig says 94, if that is right then 38-39 psi at the rail would be right not 49 psi.

Thanks guys for posting.

Yeah, If I recall, 40lbs of pressure is what the OEM 94 1500 calls for.

I am going to pull fuel injectors and and try to find which ones are bad by using the dead cylinder method..but I that's a spotty method.

Any ideas?

Alright team,

I've got some more info.

I ohm'd all the injectors to see if I electrically fried any of them... all within 14.7-14.9 of resistance; dead end. I looked at the throttle body and she doesn't look terrible, and the IAC doesn't look like any gunk is on the solenoid, HOWEVER, when I unplugged the IAC and ran the motor: she idled alot better and wouldnt stall out of me at all.

But, I know the OEM idle is 700-800ish, and I idle at roughly 450 with the IAC and 600 without the IAC. Could she dirty? Doesn't look like without tearing the TB off.

Any ideas on what else to check????

IAC....is that solenoid supposed to move about 1/8th inch? Because the solenoid doesn't seem to be acting properly/

any new parts you have might be bad even tho they are brand new


I find that autozone or similar stores have bad parts, I had 2 brand new battery from autozone go bad with days of installing them

3rd one finally turned out ok


long story short, any of those parts you replaced might be bad even tho they are new

sounds like plenty of fuel and spark is what you have, but im confused now

does it idle?

are you sure all the parts you put on are in correct?

years ago I did a full tune up and didn't tighten 1 plug wire and couldn't figure it out, finally I popped it on and the truck ran fantastic

might be a vac leak, bad plug? any codes?

It finally runs, decently. Almost better each time I drive it, but not nearly up to par..

It will idle great, 1200 when I first start the truck for a minute or two, then 700-800 consistently and, when coming off throttle she doesn't stall.

But, she stutters bad when driving, surges when you put it in reverse. The exhaust will backfire once warmed up. I wonder if I do have a clogged injector still.. I will do the "dead cylinder" test by pulling the connectors at idle after work this weekend.

No codes are thrown, at all.

I would hope all the parts I put on are correct.. but you know how it goes. Exhaust is fully welded up with a 3" MagnaFlow cat with o2 hookup, fuel pump measures fine under load as well.

I plan on changing the oil (originally put seafoam in there too when I first got the truck a month or so ago), all the spark plugs again to check for color. I fixed a vaccum leak recently as well (such brittle tubes ha), but I could test for vacuum leaks.

Anyway to test out the plug wires via multimeter?

Yes you can ohm's test the wires, old school but it still works. Look for a TSB about wire lead routing.

Edit; Link to TSB http://dodgeram.info/tsb/1998/18-48-98/18-48-98-v8.htm

Merc225hp said:

Yes you can ohm's test the wires, old school but it still works. Look for a TSB about wire lead routing.

Edit; Link to TSB TSB 18-48-98

Click to expand...

This could be the cause of the poor running conditions under load? I have never heard of plug wires causing misfiring due to them touching. The previous owner doesn't have any clips on the wires for routing really..

Looks like new plugs and wires are going in now too..

These motors suffer from cross fire bad, no place for cheap wires. Before I went to the MSD 8.5mm super conductor wires I followed this TSB always. I run wire separators and am ocd on wire routing. The other wire I would use is Magnecor.

MAGNECOR Race Wires: WELCOME TO MAGNECOR!

Changed wires and used new separators for each; 8mm. Runs better! Still surging terribly, and backfiring, missing.

So I used the dead cylinder technique, but asked for another set of ears to help distinguish which cylinders were having problems. When I put new wires, I also checked my spark plugs for fouling. Cylinders 5 and 6 had black plugs.. I am guessing I have a clogged "open" injector?

Thoughts before I sling another 100$ out the door??