Sinsectan
Registered User
I've been chasing down a misfiring, knocking, and smoking cold start issue on my 88 F250 7.3 ZF5, and could really use some input. I bought the truck that way, after the previous owner had replaced the IP, injectors, had a valve job and head resurfacing done, along with many other miscellaneous parts. The truck was cheap so I've been taking my best crack at it.
The white smoke smelled like raw diesel, so the first thing I did was go over every possible entry point for air intrusion. There's air right after the IP return fitting, which is odd, but I've confirmed that it's air tight everywhere else.
Looking through the receipts he gave me, the injectors and IP were from from Pensacola diesel, and knowing their bad reputation, I pulled the injectors and shimmed them all up to 1900psi. They were all over the place before.
The truck now runs butter smooth at idle when warm, but the bad cold start still persists. Also, now when I rev past 1000rpm, it blows white smoke, which it didn't before.
I noticed that the #1 and #2 cylinder exhaust manifolds are cold when it's warming up, telling me that they're not firing. They get warm once the engine warms up, but still cooler than the others.
I'm going to do a compression test next, and I'm just hoping it's not a head gasket or stuck ring.
Could it be a bent/loose rocker? Worn out cam? A clogged lifter? Bad IP timing?
Any input is greatly appreciated. Thanks in advance.
The white smoke smelled like raw diesel, so the first thing I did was go over every possible entry point for air intrusion. There's air right after the IP return fitting, which is odd, but I've confirmed that it's air tight everywhere else.
Looking through the receipts he gave me, the injectors and IP were from from Pensacola diesel, and knowing their bad reputation, I pulled the injectors and shimmed them all up to 1900psi. They were all over the place before.
The truck now runs butter smooth at idle when warm, but the bad cold start still persists. Also, now when I rev past 1000rpm, it blows white smoke, which it didn't before.
I noticed that the #1 and #2 cylinder exhaust manifolds are cold when it's warming up, telling me that they're not firing. They get warm once the engine warms up, but still cooler than the others.
I'm going to do a compression test next, and I'm just hoping it's not a head gasket or stuck ring.
Could it be a bent/loose rocker? Worn out cam? A clogged lifter? Bad IP timing?
Any input is greatly appreciated. Thanks in advance.