74 2.0L, Running Very Rich, owner quite confused, need diagnostic help Options

[r_towle]

no idea what an FPS is nor a TVS.
The MPS does not have to be bolted in.

You need to chase down the vacuum leak. The fact that you replaced gaskets it good, but you may have made a mistake when you put the intake system back together...
In order to rev at 4k rpms you need air.
If the throttle body is closed, you are getting air from someplace and it would be a large hole...

Check the intake like I said and redo it to ensure its super tight.
Check the injectors are in right...another vacuum leak.
Keep looking for a vacuum leak...you have one
There is no doubt, there is no question, there is no other explanation for a car that can run at 4k rpm with the throttle butterlfy closed...you need air to run that fast, and alot of it.

Rich

[drumsticks2112]

no idea what an FPS is nor a TVS.
The MPS does not have to be bolted in.

You need to chase down the vacuum leak. The fact that you replaced gaskets it good, but you may have made a mistake when you put the intake system back together...
In order to rev at 4k rpms you need air.
If the throttle body is closed, you are getting air from someplace and it would be a large hole...

Check the intake like I said and redo it to ensure its super tight.
Check the injectors are in right...another vacuum leak.
Keep looking for a vacuum leak...you have one
There is no doubt, there is no question, there is no other explanation for a car that can run at 4k rpm with the throttle butterlfy closed...you need air to run that fast, and alot of it.

Rich

Thanks Rich

FPS - fuel pressure sensor
TVS - Throttle Valve Switch (throttle body)

I will check through everything as soon as I can, thanks for taking the time to walk me through it - I'm getting quite frustrated.

-Todd

[Dave_Darling]

The MPS has a mechanical component. If you shake it back and forth, you can sometimes hear the way the engine runs change. That said, it isn't completely necessary for it to be bolted down, particularly if you're not rolling down the road. Once you're done testing, bolt the MPS back onto its bracket again.

...You still have an air leak. A big one.

--DD

[CHAZT54]

OK - we took your advice and dismantled the intake pipes and removed the throttle body assy and found the connector hoses to be pretty shoddy and the gasket at the base of the throttle body was in bad shape so we have ordered new hoses & gasket. We also found the inside of the conn. hoses to be saturated with gas/oil mix and also a puddle of gas/oil on the floor of the int. plenum.
Is this normal? or is this from the flooding out?

Somebody fill us in.

THANKS
CHAZT

[r_towle]

There is no fuel pressure sensor...a fuel pressure regulator, yes.
The TPS is the throttle position switch.

The static fuel is from the cold start valve that may be stuck open...I ended up there also...after fixing everything else.
that is kicked off by the ambient air temp sensor (mounted under the plenum)
Try routing around the cold start injector...unplug it electrically, remove the fuel from it (add a long line to route around it...

I did that...it stopped running super rich.

Rich

[CHAZT54]

There is no fuel pressure sensor...a fuel pressure regulator, yes.
The TPS is the throttle position switch.

The static fuel is from the cold start valve that may be stuck open...I ended up there also...after fixing everything else.
that is kicked off by the ambient air temp sensor (mounted under the plenum)
Try routing around the cold start injector...unplug it electrically, remove the fuel from it (add a long line to route around it...

I did that...it stopped running super rich.

Rich

yes - the fuel pressure sensor was a mis-statement. I will check out the cold start valve as you suggested. Could the pressure reg. be set too high? I haven't touched it since I bought the car a year ago so I didn't suspect a problem there.

THANKS RICH.

[r_towle]

You will need an inline gauge to confirm how the FPR is set.
I would suspect the cold start injector first...

Lets say its stuck open, and you keep getting fuel, no matter what.
If you unhook the elec, it will still be stuck open.
If you route the fuel hose around it and take it out of the loop, you wont be getting fuel anymore, but you may have created a new vacuum leak....so cap off both sides of the injector just to be safe.

I had to do this..it stopped the flooding.

IDK what your cold weather plans are, but I have driven it down to 20 degrees F with no cold start injector, no AAR, and no decel valve...it works fine without any of them till 20.
I noticed your address and you might be in the OMG it cold part of the country..but at least you can drive it till then.


rich

[CHAZT54]

There is no fuel pressure sensor...a fuel pressure regulator, yes.
The TPS is the throttle position switch.

The static fuel is from the cold start valve that may be stuck open...I ended up there also...after fixing everything else.
that is kicked off by the ambient air temp sensor (mounted under the plenum)
Try routing around the cold start injector...unplug it electrically, remove the fuel from it (add a long line to route around it...

I did that...it stopped running super rich.

Rich

yes - the fuel pressure sensor was a mis-statement. I will check out the cold start valve as you suggested. Could the pressure reg. be set too high? I haven't touched it since I bought the car a year ago so I didn't suspect a problem there.


This 914 is strictly a summer weekender and does get run once freezing temps set in. In stead of re-routing a fuel hose over to the opposite fuel rail, couldn't I just remove that hose and cap off both fuel rails at the tee? I would then leave the larger hose hooked up to the cold start valve- fuel stem & elect. connect would be capped off. Would that work OK?

THANKS RICH.

[r_towle]

There is no fuel pressure sensor...a fuel pressure regulator, yes.
The TPS is the throttle position switch.

The static fuel is from the cold start valve that may be stuck open...I ended up there also...after fixing everything else.
that is kicked off by the ambient air temp sensor (mounted under the plenum)
Try routing around the cold start injector...unplug it electrically, remove the fuel from it (add a long line to route around it...

I did that...it stopped running super rich.

Rich

yes - the fuel pressure sensor was a mis-statement. I will check out the cold start valve as you suggested. Could the pressure reg. be set too high? I haven't touched it since I bought the car a year ago so I didn't suspect a problem there.


This 914 is strictly a summer weekender and does get run once freezing temps set in. In stead of re-routing a fuel hose over to the opposite fuel rail, couldn't I just remove that hose and cap off both fuel rails at the tee? I would then leave the larger hose hooked up to the cold start valve- fuel stem & elect. connect would be capped off. Would that work OK?

THANKS RICH.

In a word, NO.
Follow the hoses back to the fuel pump and read the manual to get a detailed explaination of why that will not work. It will kill off your pump for one thing with no fluid in that part of the pump.

Rich

[CHAZT54]

There is no fuel pressure sensor...a fuel pressure regulator, yes.
The TPS is the throttle position switch.

The static fuel is from the cold start valve that may be stuck open...I ended up there also...after fixing everything else.
that is kicked off by the ambient air temp sensor (mounted under the plenum)
Try routing around the cold start injector...unplug it electrically, remove the fuel from it (add a long line to route around it...

I did that...it stopped running super rich.

Rich

yes - the fuel pressure sensor was a mis-statement. I will check out the cold start valve as you suggested. Could the pressure reg. be set too high? I haven't touched it since I bought the car a year ago so I didn't suspect a problem there.


This 914 is strictly a summer weekender and does get run once freezing temps set in. In stead of re-routing a fuel hose over to the opposite fuel rail, couldn't I just remove that hose and cap off both fuel rails at the tee? I would then leave the larger hose hooked up to the cold start valve- fuel stem & elect. connect would be capped off. Would that work OK?

THANKS RICH.

In a word, NO.
Follow the hoses back to the fuel pump and read the manual to get a detailed explaination of why that will not work. It will kill off your pump for one thing with no fluid in that part of the pump.

Rich

OK - so I need to replace the hose feeding the CSV with a longer one that will reach accross the engine and connect to the tee on the opposite fuel rail?
- and cap off the fuel line barb on the CSV and leave the elect. wires disconnected?

[Rand]

I just pulled the line off the CSV and plugged it... A pin that fit tightly and clamped.

[r_towle]

There is no fuel pressure sensor...a fuel pressure regulator, yes.
The TPS is the throttle position switch.

The static fuel is from the cold start valve that may be stuck open...I ended up there also...after fixing everything else.
that is kicked off by the ambient air temp sensor (mounted under the plenum)
Try routing around the cold start injector...unplug it electrically, remove the fuel from it (add a long line to route around it...

I did that...it stopped running super rich.

Rich

yes - the fuel pressure sensor was a mis-statement. I will check out the cold start valve as you suggested. Could the pressure reg. be set too high? I haven't touched it since I bought the car a year ago so I didn't suspect a problem there.


This 914 is strictly a summer weekender and does get run once freezing temps set in. In stead of re-routing a fuel hose over to the opposite fuel rail, couldn't I just remove that hose and cap off both fuel rails at the tee? I would then leave the larger hose hooked up to the cold start valve- fuel stem & elect. connect would be capped off. Would that work OK?

THANKS RICH.

In a word, NO.
Follow the hoses back to the fuel pump and read the manual to get a detailed explaination of why that will not work. It will kill off your pump for one thing with no fluid in that part of the pump.

Rich

OK - so I need to replace the hose feeding the CSV with a longer one that will reach accross the engine and connect to the tee on the opposite fuel rail?
- and cap off the fuel line barb on the CSV and leave the elect. wires disconnected?

That is exactly what I did.
Its about 2-3 feet of new hose and a few clamps...done.
Use the old hose and old clamps to close off the cold start injector just in case its stuck open.
I unplugged the elec first and that made no difference for me, so it may have been stuck open or leaking on mine...I never bothered to check.

Again, it really only comes into play when its really cold...otherwise its never used.
I suspect that is why it gets rusted and stuck...its used very rarely.

Rich

[CHAZT54]

EUREKA!!
It finally runs & idles normal. That CSV must have been a main culprit all along because I never did find a major vac leak.

Thanks again for all your help. Now I 'd better change the oil and get rid of the diluted stuff.
CHAZT