Fuel Injection Question
Thread Starter
|
New User
Joined: Sep 2012
Posts: 14
Likes: 0
Fuel Injection Question
I've been working on an '89 F250 project truck foe quite a while now. I took the engine out of another truck I have and swapped it into the F250. The engine was running and has about 10k miles on it. The only thing I did to the engine was put a new cam in it. 186 intake, 197 exhaust and 115 degrees separation. Here's the problem... it starts and runs smooth for 5 to 10 seconds and then stumbles and dies. I can keep it running if I pump the gas, but if I hold the throttle steady at any rpm it will stumble and die. I'm wondering if the problem is because the fuel injection needs to be tuned for this cam. I've cleaned and rebuilt the fuel system and it runs 35 PSI. I believe I've already replaced ALL the EFI sensors. The ignition system checks out perfect. The only code I'm getting is 32, an egr problem. I didn't think the cam would be such a big problem for the SD EFI, but I don't know what else the problem could be. Anybody got any ideas... cause I'm clean out!
FTE Legend
Joined: Jun 2006
Posts: 31,930
Likes: 1,499
From: Ottawa, Ontario
No the cam is not the problem, but the EGR could be. The EGR valve should be closed at idle and at all rpms before the engine reaches operating temp. Valve position is regulated by the computer via a vacuum solenoid so it should not get a steady vacuum signal from the intake.. just in case you have it connected that way now. If it is connected correctly but the valve is still opening at cold start pull the vaccuum line off the valve and see if that helps, if it does you have a problem with the solenoid, the wiring between it and the computer, or the computer itself.
Thread Starter
|
New User
Joined: Sep 2012
Posts: 14
Likes: 0
Thanks for the help Conanski. Actually I believe the the vacuum hose is connected to the manifold, so I'll change that to a ported source and put a new EGR solenoid on it. I'm keeping my fingers crossed...
Thread Starter
|
New User
Joined: Sep 2012
Posts: 14
Likes: 0
OK, I replaced the EGR position sensor and it still does the same thing. I can keep it running as long as I keep revving the engine. As soon as I hold the throttle steady, at any rpm, it dies. Bad catalytic converter, maybe? I'm open to all ideas.
Cargo Master
Joined: Apr 2003
Posts: 2,408
Likes: 5
From: Parkesburg PA
Did you change the EGR valve itself?
The engine dies after 5-10 seconds if left at a steady state, correct? So if you hold 1,500 RPMs steady it will die? Or is it only at idle. 35psi fuel sounds a little low, unless that's with the vacuum line on. Does it change when you remove the vacuum line. Also, when the engine dies is the fuel pressure still at 35psi?
Can you check for spark when the engine dies? How about the fuel injectors, are they firing? If it's got spark, fuel pressure, and the injectors are firing then the computer is likely messing with the fuel.
Another though, verify the timing is set about 10° BTDC. It will run if the timing is way off, but not well and may cause issues as the computer adjusts the timing. Physically verify TDC on #1, make sure the damper hasn't moved and then time it to 10-14° BTDC. Some cams like more base ignition timing.
The engine dies after 5-10 seconds if left at a steady state, correct? So if you hold 1,500 RPMs steady it will die? Or is it only at idle. 35psi fuel sounds a little low, unless that's with the vacuum line on. Does it change when you remove the vacuum line. Also, when the engine dies is the fuel pressure still at 35psi?
Can you check for spark when the engine dies? How about the fuel injectors, are they firing? If it's got spark, fuel pressure, and the injectors are firing then the computer is likely messing with the fuel.
Another though, verify the timing is set about 10° BTDC. It will run if the timing is way off, but not well and may cause issues as the computer adjusts the timing. Physically verify TDC on #1, make sure the damper hasn't moved and then time it to 10-14° BTDC. Some cams like more base ignition timing.
Thread Starter
|
New User
Joined: Sep 2012
Posts: 14
Likes: 0
I re-checked the error code for 32 and it only refers to the position sensor so that's all I replaced. The egr looks good to me.
I can keep the engine running as long as I keep pumping the gas but as soon as I stop, it runs for maybe 5 secs and then dies. I can get it up to 3000 rpm and it will die after about 5 secs of steady throttle. It runs great as long as I keep pumping the gas. Fuel pressure is 35 with the vac line on... I cleaned both gas tanks and installed new lift pumps, new high pressure pump, rebuilt injectors and a new pressure regulator. I verified the spark while it's running and dying. The coil is getting 12v when it's running, while it's dying and after it has stopped. I took the computer to NAPA and had it checked. They said it's good. I can play with then ig timing some but I can't put a light on it because it wont idle.
What do you think about the possibility of the catalytic converter being plugged?
I can keep the engine running as long as I keep pumping the gas but as soon as I stop, it runs for maybe 5 secs and then dies. I can get it up to 3000 rpm and it will die after about 5 secs of steady throttle. It runs great as long as I keep pumping the gas. Fuel pressure is 35 with the vac line on... I cleaned both gas tanks and installed new lift pumps, new high pressure pump, rebuilt injectors and a new pressure regulator. I verified the spark while it's running and dying. The coil is getting 12v when it's running, while it's dying and after it has stopped. I took the computer to NAPA and had it checked. They said it's good. I can play with then ig timing some but I can't put a light on it because it wont idle.
What do you think about the possibility of the catalytic converter being plugged?
FTE Legend
Joined: Jun 2006
Posts: 31,930
Likes: 1,499
From: Ottawa, Ontario
But did you do the vacuum test I suggested above and physically observer the valve position?
Trending Topics
Thread Starter
|
New User
Joined: Sep 2012
Posts: 14
Likes: 0
I'm having trouble locating a ported vacuum source. There doesn't seem to be a ported source on the throttle body or int. manifold. But, I did disconnect the vacuum to the egr and it didn't solve the problem. In fact it ran a little worse.
I'm still trying to understand the vacuum diagram but it appears there is a ported vacuum switch mounted next to the coil, and it's computer controlled. but nothing has ever been connected to it.
I'm still trying to understand the vacuum diagram but it appears there is a ported vacuum switch mounted next to the coil, and it's computer controlled. but nothing has ever been connected to it.
FTE Stories
Ford Trucks for Ford Truck Enthusiasts
3 Best / 3 Worst Parts of Modern Ford Ownership
Brett Foote
10 Amazing Upgrades That Solve Common Ford Truck Owner Headaches
Pouria Savadkouei
Every 2026 Ford Engine Explained
Brett Foote
10 Ugly Ford Trucks That We Still Kinda Love
Joe Kucinski
10 Things Every Truck Owner NEEDS (2026 Edition)
Michael S. Palmer
Rezvani's Latest Post-Apocalyptic Monster Is a Ford F-150 Raptor Underneath
Verdad Gallardo
Top 10 Most Expensive Ford Trucks Ever Sold on Bring a Trailer
Joe Kucinski
2027 Ford Super Duty Buyer's Guide (Every Model, Engine, & Package)
Brett Foote
Top 10 Ford Truck Tragedies
Joe Kucinski
FTE Legend
Joined: Jun 2006
Posts: 31,930
Likes: 1,499
From: Ottawa, Ontario
This is an EFI motor there is no such thing.
That could be a problem, the EVR (EGR Vacuum Regulator) is the solenoid at the front of the bracket where the coil is mounted, one port of this solenoid is supposed to be connected to manifold vacuum and the other to the EGR valve.
Thread Starter
|
New User
Joined: Sep 2012
Posts: 14
Likes: 0
I've been looking at the vacuum diagram and it looked like Greek to me. But I found a list of abbreviations on another thread and did some computer searches and now I'm starting to understand it. I'm going to get some more vacuum hose tomorrow and get it corrected. And thanks for that picture. It helped me verify what I was looking at.
Thread Starter
|
New User
Joined: Sep 2012
Posts: 14
Likes: 0
Paul, Thanks for all the help. The truck's running much better. I can actually get it to idle now, although it's rough. I checked the cats and they are in good shape. I have one more question. Should I be able to blow air through the EVR with the key on? It seems to me the EVR should be closed when you're trying to start it.
Lead Driver
Joined: Jul 2007
Posts: 7,868
Likes: 9
From: Rhode Island
It depends on what port you're blowing through. The EVR has the manifold vacuum port, the EGR valve port, and another fresh air port. With the valve "off" you should be able to blow through the EGR valve port, and air will come out the fresh air vent.
The vacuum port should be completely sealed with the valve off.
The vacuum port should be completely sealed with the valve off.
Thread
Thread Starter
Forum
Replies
Last Post
twicelow
Big Block V8 - 385 Series (6.1/370, 7.0/429, 7.5/460)
13
Sep 3, 2009 12:30 PM
RichardW`
Small Block V8 (221, 260, 289, 5.0/302, 5.8/351W)
23
Apr 15, 2005 10:41 AM
IES
1987 - 1996 F150 & Larger F-Series Trucks
6
May 2, 2003 11:57 PM