P38A Slow to rev, down on power

This site contains affiliate links for which LandyZone may be compensated if you make a purchase.

Bix

Loading...
Full Member
Posts
3,706
Location
Yeovil
Howdy, hoping for someone with more ideas than I do has some clues.
FIP was replaced in October, failed November. Finally got her back with a new FIP on Wednesday. Guy said she is down on power, but after the last one died was hesitant to chase any.
Fair enough, don't want to dump gallons of fuel on floor again. Was fine if a little slow driving home. Happy days.

Yesterday went to head into town, refuses to build Boost. Unplugged MAF, nothing. Limped home and had a look, turns out the Boost control solenoid was unplugged and had detached from the firewall (the brackets it bolts to are only glued on it seems). Plugged it back in, cable tied into place, was back to how it was Wednesday. Happy days went about my day.

Today went to head into town again, nothing. Doesn't rev past idle in gear so couldn't even leave the parking spot, let alone the street. Had another look, everything was still where it should be, double weird.

Wife came out and asked me what I'd have done if a customer car came in no power, made me think of a Landy came in with similar symptoms, that was the EGR stuck open flooding the engine with exhaust. So I unplugged the vacuum hose and blocked it off which gave me back some power, not quite what it was like Wednesday, but not far off.

In my head the EGR is suspect, possibly stuck open, but without the vacuum it should be closed so I'll try the coin trick to block it and see if that helps.
But is it possible the boost solenoid was damaged when it detached from the firewall and started bouncing around and possibly needs replacing too?

Thanks.
 
Howdy, hoping for someone with more ideas than I do has some clues.
FIP was replaced in October, failed November. Finally got her back with a new FIP on Wednesday. Guy said she is down on power, but after the last one died was hesitant to chase any.
Fair enough, don't want to dump gallons of fuel on floor again. Was fine if a little slow driving home. Happy days.

Yesterday went to head into town, refuses to build Boost. Unplugged MAF, nothing. Limped home and had a look, turns out the Boost control solenoid was unplugged and had detached from the firewall (the brackets it bolts to are only glued on it seems). Plugged it back in, cable tied into place, was back to how it was Wednesday. Happy days went about my day.

Today went to head into town again, nothing. Doesn't rev past idle in gear so couldn't even leave the parking spot, let alone the street. Had another look, everything was still where it should be, double weird.

Wife came out and asked me what I'd have done if a customer car came in no power, made me think of a Landy came in with similar symptoms, that was the EGR stuck open flooding the engine with exhaust. So I unplugged the vacuum hose and blocked it off which gave me back some power, not quite what it was like Wednesday, but not far off.

In my head the EGR is suspect, possibly stuck open, but without the vacuum it should be closed so I'll try the coin trick to block it and see if that helps.
But is it possible the boost solenoid was damaged when it detached from the firewall and started bouncing around and possibly needs replacing too?

Thanks.
What car is this? If a P38, the EGR valve can certainly stick open. I run mine with the vacuum tube disconnected and blocked with an M5 screw except when they go for the MOT.
Boost solenoid on the bulkhead? What's that and where precisely?
 
What car is this? If a P38, the EGR valve can certainly stick open. I run mine with the vacuum tube disconnected and blocked with an M5 screw except when they go for the MOT.
Boost solenoid on the bulkhead? What's that and where precisely?
Yes, 2.5 P38.
I was pondering the possibility of it sticking open without the vacuum line disconnected.

It sits behind the EAS compressor against the bulk head. One of the outlets goes to the EGR, one has an air filter on it, the other I haven't worked out where it goes to yet.
STC4198A-Aftermarket.jpg
 
Yes, 2.5 P38.
I was pondering the possibility of it sticking open without the vacuum line disconnected.

It sits behind the EAS compressor against the bulk head. One of the outlets goes to the EGR, one has an air filter on it, the other I haven't worked out where it goes to yet.
View attachment 332062
That is not a boost solenoid, the the control valve for the EGR. The other pipe goes to the vacuum pump on the front of the cam cover. The EGR valve can certainly get coked up and stick.
 
That is not a boost solenoid, the the control valve for the EGR. The other pipe goes to the vacuum pump on the front of the cam cover. The EGR valve can certainly get coked up and stick.
That was my understanding, but everywhere I've looked has it as a boost control solenoid. Guess it's the same thing just used differently?
I've have a further investigation tomorrow when the rain stops.
 
That was my understanding, but everywhere I've looked has it as a boost control solenoid. Guess it's the same thing just used differently?
I've have a further investigation tomorrow when the rain stops.
The photo you posted is too small to see clearly but it does not look like the correct item.
 
The photo you posted is too small to see clearly but it does not look like the correct item.
This is the offender. The studs it attaches to are only glued to the bulk head and they had separated ways, some how the plug in it had become detached. I tried to cable tie it back in place, not pretty but is holding for now.

20241220_175306.jpg
 
This is the offender. The studs it attaches to are only glued to the bulk head and they had separated ways, some how the plug in it had become detached. I tried to cable tie it back in place, not pretty but is holding for now.

View attachment 332064
Yes, that's the one for the EGR. The studs were welded to the bulkhead, looks like they may have rusted off from your photo.
Except for the MOT, you do not need it, leave the pipe off the EGR valve at the manifold and block the end of the rubber pipe with an M5 screw. Worth taking the EGR valve off and giving it a good decoke then there is no need to block anything as with the pipe off the valve will stay closed.
 
Yes, that's the one for the EGR. The studs were welded to the bulkhead, looks like they may have rusted off from your photo.
Except for the MOT, you do not need it, leave the pipe off the EGR valve at the manifold and block the end of the rubber pipe with an M5 screw. Worth taking the EGR valve off and giving it a good decoke then there is no need to block anything as with the pipe off the valve will stay closed.
So I checked all of this, came back EGR clean, that vacuum has been blanked off. I have no power when engine is cold, slow to rev, put it in drive and it won't lift off of idle. Zero power. Leave her to run for 20odd minutes to get toasty and I can at least move, low power but I can move. Sounds like she generates boost at about 2.3-2.5k then away.

I've unplugged MAF to rule that out, and it's the same outcome so I'm confident that isn't the issue.

think I have 2 options left, MAP sensor is duff, not sure how to test that without just replacing it.
Or FIP is duff? I've seen the fuel pressure switch can be a fail point, I could swap it from the other dead pump and see if that resolves the issue, but as it seems temp sensitive, I have doubts. Fuel temp sensor inside the pump I guess. Anything else I should check before condemning another FIP?
 
So I checked all of this, came back EGR clean, that vacuum has been blanked off. I have no power when engine is cold, slow to rev, put it in drive and it won't lift off of idle. Zero power. Leave her to run for 20odd minutes to get toasty and I can at least move, low power but I can move. Sounds like she generates boost at about 2.3-2.5k then away.

I've unplugged MAF to rule that out, and it's the same outcome so I'm confident that isn't the issue.

think I have 2 options left, MAP sensor is duff, not sure how to test that without just replacing it.
Or FIP is duff? I've seen the fuel pressure switch can be a fail point, I could swap it from the other dead pump and see if that resolves the issue, but as it seems temp sensitive, I have doubts. Fuel temp sensor inside the pump I guess. Anything else I should check before condemning another FIP?
In tank pump OK? How much fuel in the tank? Check the fuel flow at the filter. Is the filter clean or has it got the dreaded black mould in there? Is the pipe from the manifold to the MAP sensor and the manifold spigot clear? It really needs diagnostics rather than chucking parts at it.
 
In tank pump OK? How much fuel in the tank? Check the fuel flow at the filter. Is the filter clean or has it got the dreaded black mould in there? Is the pipe from the manifold to the MAP sensor and the manifold spigot clear? It really needs diagnostics rather than chucking parts at it.
In tank pump was replaced a few years back, will run right down to the bottom of the gauge, so gonna say good. Currently sat with a full tank. I'll check the filter for flow and cleanliness. As I recall, when the glow plugs are on I should have a constant flow of fuel?
I'm guessing the pipe from the manifold to the map sensor is the same diameter as the fuel spill off pipe? It appears clear, but also seems aged, probably won't hurt to replace it and I have some spare.
Diag is a mare, no one will touch it or have a huge backlog. Really should've got one years ago when I had more disposable income. I'll try and get it booked in.
 
In tank pump was replaced a few years back, will run right down to the bottom of the gauge, so gonna say good. Currently sat with a full tank. I'll check the filter for flow and cleanliness. As I recall, when the glow plugs are on I should have a constant flow of fuel?
I'm guessing the pipe from the manifold to the map sensor is the same diameter as the fuel spill off pipe? It appears clear, but also seems aged, probably won't hurt to replace it and I have some spare.
Diag is a mare, no one will touch it or have a huge backlog. Really should've got one years ago when I had more disposable income. I'll try and get it booked in.
Yes. glow plugs on should give fuel flow but you can jump the relay. Pumps can and do fail suddenly. MAP pipe is the same as the spill pipe. Just make sure the spigot is clear.
Is there no one up your way on the LZ map with a Nanocom?
 
Yes. glow plugs on should give fuel flow but you can jump the relay. Pumps can and do fail suddenly. MAP pipe is the same as the spill pipe. Just make sure the spigot is clear.
Is there no one up your way on the LZ map with a Nanocom?
I'll give it a try in the morning and see how I get on.
Unfortunately the closest people haven't been on the forums for 6 years. Nearest after that is over an hour away, so I'll try to exhaust local garages. Maybe I'll get lucky.
 
Back
Top