Sagerific95
New Member
- Joined
- Apr 15, 2024
- Messages
- 14
- Reaction score
- 1
- Points
- 3
- Location
- Connecticut
- Vehicle Year
- 1994
- Make / Model
- B4000
- Transmission
- Manual
Hey everyone, I’m a new member but I’ve been reading on this forum for years, I’m finally posting because I’ve run out of information to help me fix my truck…
So here’s the story. 3 years ago I purchased a 94’ B4000 SE, standard shift with high miles. The transmission was in the bed of the truck because 3rd gear was blown. I purchased a 1993 ranger 4.0 with a rotten frame from my buddy as a donor vehicle for my B4000, had less miles on it, ran fine and was a good candidate for an engine rebuild/ donor for my B4000.
The original engine had EGR,
The tube from the manifold to EGR valve was broken and the truck always ran terribly.
Fast forward to 2024, I rebuilt the 93’ engine completely with new bearings, and rings, with new aftermarket heads that are reinforced. As far as I can tell they are the older style larger chamber, however these heads were as cast and the chambers are pretty rough surfaces.
When I rebuilt the engine I used the 93’ intake manifold to get rid of the EGR as my truck does not need emissions where I live.
NOW HERES WHERE THE FUN BEGINS…
Every single sensor on the engine is new, including a Reman Dorman ECU for a 1993 from rock auto (capacitors were bad, I found out after reading about them on this forum), as well as injectors and here’s everything I know from trying to figure this out for 3 years:
- compression is fantastic in all cylinders, 185-190 psi across the board.
- tps setting is correct.
- fuel pressure is within spec, no fuel coming from FPR vacuum line.
- no vacuum leaks, smoke test confirmed.
- engine idle drops to +or- 550rpm when IAC is unplugged, engine does not stall.
- engine runs the same when MAF is unplugged.
- thermostat operates normal and is a 198F.
The only new but suspected to be bad components are the injectors, at the time of the rebuild I couldn’t afford the name brands and got a set for 80$ from Amazon.
Here’s what the problems are:
- the engine runs fine on choke mode.
- Once the engine is warm, the idle hunts and never stops hunting, sometimes it almost stalls as the rpm’s fall, but it always runs.
- Fuel mileage is about 11-13 mpg.
- No CEL ever.
- I HAVE to run 93oct fuel otherwise it detonates under load at highway speeds.
- On hot starts the engine misfires on 1 cylinder until I punch it and then it seems to go away.
- The engine always gets me where I need to go, but it always runs poorly. Gets bad Gas Mileage, and always idles like crap.
I know this was a long read, I appreciate anyone who has input. I’m an automotive mechanic, I’ve been out of the field for about 5 years, I work in aerospace now. I still have all my tools, a bit of knowledge and understanding. As we know there isn’t much communication from the ECU on these engines. I’m hoping somebody can help. It’s great to be here!
So here’s the story. 3 years ago I purchased a 94’ B4000 SE, standard shift with high miles. The transmission was in the bed of the truck because 3rd gear was blown. I purchased a 1993 ranger 4.0 with a rotten frame from my buddy as a donor vehicle for my B4000, had less miles on it, ran fine and was a good candidate for an engine rebuild/ donor for my B4000.
The original engine had EGR,
The tube from the manifold to EGR valve was broken and the truck always ran terribly.
Fast forward to 2024, I rebuilt the 93’ engine completely with new bearings, and rings, with new aftermarket heads that are reinforced. As far as I can tell they are the older style larger chamber, however these heads were as cast and the chambers are pretty rough surfaces.
When I rebuilt the engine I used the 93’ intake manifold to get rid of the EGR as my truck does not need emissions where I live.
NOW HERES WHERE THE FUN BEGINS…
Every single sensor on the engine is new, including a Reman Dorman ECU for a 1993 from rock auto (capacitors were bad, I found out after reading about them on this forum), as well as injectors and here’s everything I know from trying to figure this out for 3 years:
- compression is fantastic in all cylinders, 185-190 psi across the board.
- tps setting is correct.
- fuel pressure is within spec, no fuel coming from FPR vacuum line.
- no vacuum leaks, smoke test confirmed.
- engine idle drops to +or- 550rpm when IAC is unplugged, engine does not stall.
- engine runs the same when MAF is unplugged.
- thermostat operates normal and is a 198F.
The only new but suspected to be bad components are the injectors, at the time of the rebuild I couldn’t afford the name brands and got a set for 80$ from Amazon.
Here’s what the problems are:
- the engine runs fine on choke mode.
- Once the engine is warm, the idle hunts and never stops hunting, sometimes it almost stalls as the rpm’s fall, but it always runs.
- Fuel mileage is about 11-13 mpg.
- No CEL ever.
- I HAVE to run 93oct fuel otherwise it detonates under load at highway speeds.
- On hot starts the engine misfires on 1 cylinder until I punch it and then it seems to go away.
- The engine always gets me where I need to go, but it always runs poorly. Gets bad Gas Mileage, and always idles like crap.
I know this was a long read, I appreciate anyone who has input. I’m an automotive mechanic, I’ve been out of the field for about 5 years, I work in aerospace now. I still have all my tools, a bit of knowledge and understanding. As we know there isn’t much communication from the ECU on these engines. I’m hoping somebody can help. It’s great to be here!