stupidnoob

I have had nothing but problems with this vehicle and I keep costing the customer (my parents) LOTS of money. I put this in general as it seems to have more hits than the "express van" section and its a 5.7l drivability concern.

It came to me about a year ago needing a motor, It had a horrible rod knock and other clattering. I purchased a rebuilt long block from cylinder head specialties in Portland (DON'T do business with them, halfway nice guy but if you make him mad he insta-snaps into douche bag wont help you at all, took me 6 months, a demand letter and BBB involvement to get my core charge back.

Anyway since day one this thing has been a problem, oil leaks, coolant leaks, misfire... EVERYTHING has been replaced, motor, radiator, distributor, exhaust manifolds, plugs wires cap rotor, hoses, cooler lines... as of today it got a new-new front cover, new oil pan gasket (to combat some leaks) and a MFI conversion to hopefully solve my weird warm idle misfire. If its not apparent the MFI conversion didn't work. I am getting nearly maxed out at idle +24 on my B1 and +/- +20 B2. My vacuum gauge shows about 15in hg at idle in gear (about 600rpm, estimating because I didn't look at the scan tool and no tach). Cold it idles perfect and drives great, but warm it starts missing.

I don't know where to go from here, today was a nearly 500 dollar endeavor with the conversion kit and gaskets, I didn't check my spark plugs (that were new when the motor went in like 2k miles ago), but I have run some top engine cleaner through the old injector setup. I want to pull one but have had a long day and don't know how sleep will be tonight considering my extended weekend is turning into a working on this nightmare.

tomorrow, Ill pull the plugs and replace them if they are coated, (ill note their condition for a follow up tomorrow). maybe run some propane around the intake manifold and monitor my short term. I haven't checked recently but using a co-workers genisis I was able to see my misfiring cylinders were 5 and 7 predominately. Ill have to borrow it again. also I have not been able to do a ckp relearn as you have to be above 160 degrees I believe and for some reason I cannot get above like 155 with a tested, fully functional thermostat. NO DTC's!

Insult to injury, I think the oil leak is still there yay!

72c10gunn

Have you pulled the egr valve off and cleaned it?

stupidnoob

EGR valve crossed my mind last night when I was trying to decide my next step...

For the sake of discussion and understanding my only reason for not pulling it off as of yet is simply because I see a stuck EGR valve causing idle concerns warm or cold, and really cold she runs like a champ.

Ill just pop the egr tube off the manifold and plug it and see if that helps at all.

72c10gunn

ok keep us posted. hope you get these issues sorted out.

desrtrat

if missing on 5 and 7 i would check on a manifold gasket leak. try to re toque the intake again.

good luck

stupidnoob

I have had it for today I think... keep in mind this is in an express van so getting to ANYTHING is a PITA. I did compression on my #7 and came up with about 140psi. Ill hopefully be able to get it into my schools shop next week where they have alot more tools at my disposal like a labscope and 5 gas analyzer...

one thing I did notice was my coolant temperature sensor is about 30 degrees low in relation to my IAT after the vehicle sat overnight. using ohms instead of voltage drop I was able to get a general idea of circuit integrity so my only other assumption is that my ECT sensor is bad I dont see that causing any type of misfire though.

Ill retorque my intake manifold this week... the problem with being a rookie mechanic, all my good tools are across town at work and I dont have a decent selection at home.

I installed the intake manifold with the engine out of the van. torqued everything to spec, I really dont see how I could have damaged the gasket to cause a leak considering I had 100% access to everything so it was a pretty smooth process.

I think my next step will be taking a sawzall to the van to make some effing for me to get to the motor.

stupidnoob

laying in bed this morning deciding if I should end it all and drive the van into a ditch OR go ahead and re-do the lower intake manifold gaskets. I did hit me while I was attempting to adjust the valves (another reason why not to buy from CHS) I continuously followed the book to a T and all it did was open the valves... So my attempt to restart did nothing but backfire up the intake, I could see that having pushed the gasket out (possibly)... It does act VERY much like a lean misfire and my vacuum is a little low indicating a vacuum leak...

Ill follow up tonight after I have followed my first instincts this morning or delivered it back in working order.

MDTAHOE

Low vacuum does not always indicate a vac leak . Actually very rarely does it mean that. Low vac would be caused by lean fuel mixture however it would run much worse cold. Incorrect valve timing or ignition timing would cause low vac. Also a exhaust restriction would cause it. What is the vac reading at 1500 rpm? All the time and money invested in the van it could have be diagnosed and fixed by a Dealer for less. Sometimes it is better to cut your losses and pay someone. I really wish I could help you but without seeing the van it would be darn near impossible at this point.

stupidnoob

I know, I work for a chrysler dealer... and I FULLY respect that, at the same time I know (at least at my dealer) ALOT of techs wouldnt want to touch this with a 10 foot pole considering all the work that has been done to it in a driveway. ultimately I am new enough into this field I know just enough to get myself in alot of trouble!

ignition timing is controlled by the computer and the cam and crank corrilation is setup on this.

There are many things that could make it go lean, faulty o2 sensor, vac leak, not enough fuel quantity (low pressure, injectors)... I am going lean on both banks (adding 20+% on the scantool) so I would lean away from o2 sensor, or wiring for that matter, my fuel pressure was great every time I have checked it (brought my pressure kit home so ill check again). Injectors are new. Leaves me with vacuum leak, and the symptoms are much like I have seen before almost not noticable in neutral, but put a load on it (in D) and you can feel it miss, and you can step into it and the misfire all but vanishes.


for exhaust pressure, I would think it would get much worse at high rpm, high load, which this cleans up right off idle.

Looks like I am off to check my mechanical timing... I am pretty positive its good though, seems like I remember clearly verifying before the first time I put the front cover on. plus I am really only hitting on a couple cylinders according to the misfire monitor, wouldnt it be more wide spread if my mechanical timing was off?

Anyway, I fully respect your position, its almost impossible to interweb diagnose someone elses mess. I was going to be running it to the dealer today but got the bright idea to pull the intake manifold and inspect....

MDTAHOE

I can definitely tell you, I think anybody who gets the job at any shop will not be happy about it. You are right most will not want to touch it with a 10 foot pole, all you need is 1 knowledgeable guy that can figure it out. All the injectors are new? MFI conversion? Are you positive that #5 and #7 injector are not switched under the intake? Is the fuel meter body pulled all the way through the intake? Did you lube that gasket with anything? It can be very difficult to pull the meter body through. What is the upstream o2 sensor voltage? bank1 and 2. If you add propane around the intake and meter body does the short term fuel trim change? o2 voltage change?