Anyone up for a diagnostics challenge, cuz i need some assistance

CaifanSC

SCCoA Member
Unfortunatelly, this is yet ANOTHER no start problem, which im usually good at solving without having to post here...but this time i just ran out of thoughts. I've done everything I've been able to think of, and which I mention here, so plese be patient reading all my details.

Problem: Engine cranks, turns normally, it even bucks as if its about to start...but it just doesnt. Its really really REALLY close to starging, but no Cigar. Problem started out of the nothing, one day it was fine, the next morning it started shaking with rough idle, then while pulling out the driveway it shut off and ran as if it was on 4 or 5 cylinders.

What ive done to fix the problem: Recent oil change (few hundred miles ago) and full tune up, which means new motorcraft double platinums on all 6, ignition wires, fuel filter, air filter, oil filter, PCV, belts, etc). Spark plug wires are installed correctly. Crank and cam sensors are about a year old...I get VMM and Tach signal, so i doubt its the cam sensor. I visually checked the crank sensor and it looks fine, and I dont get the 'upshift' light when cranking. Both sensors and their respective wiring seems to be ok, and I have the crank bolt in place and the balancer is tightly positioned. All my fuses are OK including the ones in the engine bay, I have pretty good fuel pressure at the rail and the pump works...although i believe its a bit louder than before...and I do have enough gas...so tahts not the prob, and yes its 93 octane. I thought about dirty fuel system, but I have a habit of buying fuel system cleaners every few weeks to keepy my system clean, so i doubt thats the problem. I checked the harness that goes into the EEC and that seems ok, the EEC sounds like it operates when i turn the key to the ON position. I checked teh codes two days ago and it gave me a KOEF code #24 for the ACT (air charge temperature) sensor, which I replaced and did nothing. Now i get #24 still and #21 for the Coolant temp sensor, which is also not that long since I replaced...but these codes to me dont seem as if they could cause this type of problem. I have a spare DIS which i switched using a good heat sink coating and this didnt help and I've checked the resistance on my coil pack and it shows that its OK. Also, the battery WAS fully charged and only a few months old since I bought it from sears (Die Hard Gold), but its now weak since i've cranked the engine so much...but I use a portable charger to start the car now. Car is an 89 automatic with about 222k miles on original gaskets & tranny...and its not HG's cuz i've also checked for the typical signs....

As you can see, i've done tons of crap to check whats wrong with dear old Mustafa ( my SC's nick name), but it just wants to challenge me some more. Any help is DEARLY appreciated, as I have to go back to school in a few days and will not be able to PLAY with it for a while...that and considering that we're getting an average of 20* per day here in maryland...so its cold as crap. thanx a bunch
 
Were those codes from the key on/engine off?
Check for any vacuum leaks around the MAF, pcv, sc top, intercooler....

How is the fuel pressure?

Normally you should do the codes on a warmed up engine, that is why you get that code. 21. ECT out of range

If the ECT sensor not working right, it could cause a cold starting problem.

You might try unplugging the cranks sensor wiring and plugging back in. If connector is grimey, clean it with electrical cleaner.
 
knock sensor

it's wired to the ect and the act and the octane adjust plug.. via a black/white wire.. that's 1 idea ..other may be one of the4 fuse
links by the starter relay ..just guessing but something else to look at
 
Starting Problems

I know you checked the harmonic balancer, but just to rule it out completly have someone observe the balancer when you are cranking the engine. Make sure it does not show any signs of "wobble" or being "out of round". When mine went out the bolt was still attached, it appeared to be tight, but it was, in fact broken. The crank position sensor sits relativly close to the h/b and it might have been knocked it out of position if the balancer has moved.

Good Luck,

Mike
 
thanx for the replies guys, i'll check the knock sensor, possible vacuum leaks and for 'wobbling' on the crank pully tomorrow...i just finished re-checking each and every FAH KING spark plug and wire in 29* weather. Back is sore and i need some beer after beeing down there for a good while. I also checked through the oil cap and checked that the valves do move, so that means timing chain is OK. update soon to come...
 
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