Troubleshooting a crappy running Dodge

[Blue85]

Any help you can give will be appreciated.

Vehicle is a 94 Dodge Shadow, 4 cylinder TBI. It runs really crappy. The idle is rough enough to shake the engine in its mounts. It smooths out at higher rpms, but the power is really lacking. The exhaust smells rich all the time and it likes to stall during decel. Apparently the symptoms appeared all at once.

Here's what we checked so far:
-Ignition timing is good, every plug is firing. Removal of any plug wire makes it much worse.

-Fuel pressure is good: around 40psi. The manual says 38 or 39 is normal.

-Tests with a vacuum gauge seem normal. Specifically, we were looking for a plugged cat, but I'm not sure this test is conclusive.

-TPS is about 4500 Ohms total and seems to vary linearly throughout it's range.

-I'm not sure on the injector spray pattern. With a timing light, it looks like tiny drops. Anybody have any pictures of a good one?

-Not sure about the MAP sensor, but it runs worse without it and removing the vacuum line to it does set the MAP code.

-When it's idling and shaking, the stream from the tailpipe is "pulsing" pretty distinctly.

Here's some stuff that hasn't been checked:

-Valve timing: it could be that the belt slipped a tooth. I know it can be checked by removing the cover and lining up the dots, but I am holding off on that.

-Compression: the owner is going to do a compression test to see if there is a bad valve.

 

[unclematty]

what motor?? I used to be the 2.2-2.5 chrysler god back when. not sure what you got, sounds fishy. maybe a EGR valve stuck open, maybe a blown headgasket?

 

[unclematty]

Those stinkin 4 banger used to crack the heads between the valves all the time, only way to test was a leak down !

 

[Blue85]

It's the 2.5 with about 130,000 miles. Could a stuck EGR really make it run that bad? I guess I could remove it and plug the openings. I am thinking about building up a leakdown tester. There is no coolant in the exhaust and the car doesn't lose coolant.

 

[Blue85]

We built a leak down tester and tried it out tonight. We hooked it up to #1 and after finally getting it in TDC, we got bubbles in the coolant overflow tank. That's as far as we got. Here's a tidbit for you: these Chryslers have a timing mark for each cylinder. Some other time we will try to figure out if there's any way it was just hooked up wrong or something and also check the other cylinders.

 

[CustomChevy]

its a dodge, what do you expect

 

[Blue85]

its a dodge, what do you expect

That is what I expect. I drove a Dodge 2.2 for a while and it went through two engine rebuilds, a head swap, a computer and a pile of sensors in less than 150,000 miles. Then it threw a rod again and retired.

Last night I checked the other three cylinders. 1&2 are connected together, both blowing bubbles in the coolant and pressurizing the crankcase. 4 seems to leak into the exhaust. I guess the head will have to come off and get checked for cracks and flatness. If it's cracked, I think a reman is about $400, so the owner will have to decide if the car is worth it. If the head is good, I don't see any reason not to throw a new head gasket kit on it and wait till it breaks again. I suppose the valves should be looked at.

Any chance I am doing this leakdown testing incorrectly?

 

[diesel4me]

two ways to go..

We did several head gasket and head replacements on 2.2 and 2.5 Mopars at my friends shop--about 75% of them had the engine lose a bearing a few weeks later--the prestone got into the lower end and ate the babbit in the bearings..

He decided after the 4th car came back rapping,it was cheaper and easier to just get a used good running motor from a junkyard,and put it in..they sell them here for about 250 bucks for a low mileage one with a 60 day gaurantee--it cost him that much to have the head checked and the valves reseated!--plus the head gasket set,and all the other things it needed like hoses and a few sensors that broke when the head was being removed..just something to consider...

We also had a few of the cars need catalitic converters too--it seems prestone in the exhaust tends to clog them up pretty good--but we just ran a crowbar thru them and bolted them back up--the owners were fed up,and had spent enough on the cars as far as they were concerned!..

 

[unclematty]

Yep ! blown head gaskets very common on those chrysler 2.2/2.5 series, I love em... they make me tons of $$$$$ sorry to be the bearer of bad news

 

[R72K5]

yeh blonw head gasket is common as dirt on these yep

on this one it siound slike running way rich

i would check TPS, O2 sensor, and fuel pressure regulator and MAP/MAF sensor

sounds like should go to dealer and be plugged too computer though

about 40 or 50 bucks to have done/diagnosed
if the car is nice and you plan on keeping and driving, or fixing and selling for considerably more than yo u got it for then id take it to dealer computer

if not then dirt track it, strip it

good luck

 

[Blue85]

There was no sign of coolant from the tailpipe when it was running. We also haven't found any coolant on the dipstick, but you're right, we should drain out the oil and have a look.

I'm not going to worry about sensors anymore right now, since even the best engine controls in the world couldn't run this thing.

 

[Roz]

good running dodge? wouldnt that be an oxymoron?

 

[Thunder]

Sounds like the MAP sensor to me. Did you check the troubnle codes?

 

[Blue85]

OK, here are the pics from the teardown:

Cylinder #1:

Cylinder #2:

Cylinder #3 (you can see where I started scraping at the carbon):

Cylinder #4:

Here's the head gasket, blown out between #3 and #4:

Here is the head right above the blown area of the gasket. These little nicks seem to show up all over around the cylinders, not just in the blown out areas.

Finally, I don't know what this is, but it's #4:

 

[Blue85]

There are no trouble codes. I found no coolant in the oil and no oil in the coolant. I can't determine for sure where the air was leaking from #1 and #2 into the coolant.

 

[unclematty]

notice the cracks between the valve seats? Very common! Stick a fork in it!

 

[Blue85]

Now what if I cleaned it up, had the gasket surface refinished, threw a new head gasket in and put it back in service?

If I got a head from a junkyard, would I be able to see any cracks that would make it unuseable? I don't want to do a head rebuild and valve job.

 

[diesel4me]

Pressure test it..

Any good machine shop will pressure test a head before they will perform any valve work or refacing....many mopar 2.2/2.5 heads crack there,but not all of the cracks penatrate the water jacket--I sold many "rebuilt" heads for them that were cracked!--when I called the rebuilder,he assured me they were tested under pressure,none leaked,and he'd gaurantee they would not leak!--he said about 90% of all those heads had cracks..but only about half of them were "junk" as far as leaking coolant went..most of the cracks were cosmetic "surface cracks",and were not a big deal...Many VW engines the 2.2 was derived from (The 1.7 "rabbit" motor) had the same scenario,as did the air cooled beetle engines..

He also said trying to weld the cracks made them open up worse,and ruined the heads--so he just tests them,and leaves the "surface cracks" as they were!..I had a hard time convincing my customers though--I had to hand THEM the phone and let HIM describe why the head they just bought for 200 bucks had cracks!

 

[unclematty]

I just don't like puting my name on anything cracked. Only way to really solve it is to buy a new one $550.00 from dodge, lest someone know a less expensive way!

 

[Blue85]

Well, we found the less expensive way. There is a place in Florida (Clearwater Cylinder Head ) that sells new non-Chrysler castings pre-assembled with a used cam and reconditioned valves for $285. It comes with a 2-year warranty. Shipping was $25 to Michigan and that includes the return shipping for the core.

After the old head was cleaned up, it was clear that there was an additional crack in the top of each combustion chamber, which is how the air could get into the coolant.

I discovered after getting the engine back together that when they assemble the head they don't install the cam seal . Can you guess how I figured this out? Fortunately, a new one comes in the head gasket kit.

So other than worn out struts, a blown muffler, a leaking water pump and a possible slight fuel leak, the car is running great. I will give it back to the owner today. It's full of water and radiator flush, so I will drain that back out in a couple of days. The old head gasket actually had full blockage of some of the small coolant holes from mineral deposit. Hard to believe the head cracked, eh?