Hot, now cold start problem

[DMC3165]

Every so often I'd have a mild hot start problem. No big deal would just miss a little and idle rough only for a minute or two. It would only do it occasionally and only if it was restated within 10-15 mins. But just today it did the same thing when cold. Car had been sitting for over 12 hours. It had a tough time holding an idle, like a bad vacuum leak. But once it was running for about 5 minutes it was fine. Also did the same thing on a hot restart. My accumulator is about 2 years old and has about 20,000 miles of usage. I have never changed the o-ring in the PPR. But I think it might be electrical. I can hear the frequency valve buzzing so I think that's ok. I'm not real sure where to look next. Ideas?

[Bitsyncmaster]

If it takes that long to clear up and it's bad cold and hot then I would guess your mixture is not adjusted correctly. Other possibility is the WUR is faulty. Have you cleaned the WUR screen yet?

[David T]

My guess would also be the Warm-Up regulator AKA the Control Pressure Regulator. It is not usually fixed by cleaning the screen, they eventually lose their calibration and/or the heating element inside burns up it's connections. Verified by watching the control pressure as the motor warms up or by substitution with a known, good one. Before doing anything visually inspect the vacuum hoses to be sure they are all snugly attached and routed correctly as per the label on the engine cover.
David Teitelbaum

[Ron]

I'd guess vacuum leak or WUR/CPR too.
(And forget the accumulator WRT to idle).

[DMC3165]

Definitely an intermittent problem. Car started ok this morning. Could it be something related to ambient temperature? It was cold this morning but warm yesterday afternoon.

[DMC3165]

While I was in the procees of diagnosing my dead fuel pump today I found something interesting. After i got the car running again ( and it still idled like crap when cold) I sprayed ether near the intake manifold. I found the engine raced a little when I sprayed ether near the cylinder port that was closest to the firewall on the passanger side. I'm not sure if that's actually where it's going into the engine from being there are alot of vacum lines in the area and those gaskets were replaced about 2 years ago. But it's getting in from somewhere in that area. I snugged up the bolts just a little but I don't think that made any difference. Does this definetley sound like a vacum problem or an intake manifold gasket problem?

[Ron]

Does this definetley sound like a vacum problem or an intake manifold gasket problem?Same difference...

Take a garden hose, turn it way down to a trickle and go fishing...
You should hear it slurp and probably change the way it runs when you get to a leak.

[DMC3165]

Same difference...

Take a garden hose, turn it way down to a trickle and go fishing...
You should hear it slurp and probably change the way it runs when you get to a leak.

Seriously? Pour water on it? I was thinking of just trying to put a bead of silicone around it so i don't have to take the whole manifold and mixture unit off. But if pouring water on it is safe to do I'll try it.

[Ron]

It is rare that you can get away with silicone, unless you take it apart and use it when going back together...and I wouldn't do that on a D intake anyway.

A trickle won't come close to hurting it. Now you shouldn't pour cold water on a HOT engine. And coolant isn't a good thing to get in the valley because it doesn't evaporate like water. But, water gets splashed on engines all the time...sometimes ice cold slush. Haven't you seen people spraying off their engine at the car wash (and most leave them running so it will not be hard to start if the get the ignition wet, etc)

(Getting ether around the distributor is when things will get exciting. :flamed:)

[David T]

The best way to go looking for vacuum leaks is with a smoke machine. You probably need new injector seals and a vacuum hose may be loose or disconnected on the front of the intake manifold.
David Teitelbaum

[Jimmyvonviggle]

You can try a smoke pencil that is used to check for leaks around doors and windows.

[Ron]

The best way to go looking for vacuum leaks is with a smoke machine. You probably need new injector seals and a vacuum hose may be loose or disconnected on the front of the intake manifold.
David Teitelbaum
Agreed. But when the leak is large and your budget is small....

[David T]

Agreed. But when the leak is large and your budget is small....

A good visual inspection costs nothing. See if the injectors are loose and the seals are hard. Look around the front of the motor at all of the vacuum connections. If you smoke, you can try blowing smoke at the motor and see what happens. I do not like the idea of spraying water at the top of the motor to look for leaks. It is messy and you will get some into the spark plug wells and we all know what that can do. Maybe you can find a local garage with a smoke machine and they wouldn't charge much.
David Teitelbaum

[Ron]

Me thinks you may have backslid on your promise about skimming...


A good visual inspection costs nothing.
He did a visual inspection and said he wasn't sure...


See if the injectors are loose and the seals are hard. Look around the front of the motor at all of the vacuum connections.
He said it reacted to ether near the rear of the engine...


If you smoke, you can try blowing smoke at the motor and see what happens. I do not like the idea of spraying water at the top of the motor to look for leaks. It is messy and you will get some into the spark plug wells and we all know what that can do. Maybe you can find a local garage with a smoke machine and they wouldn't charge much.
David Teitelbaum
The suggestion was a trickle of water in the suspected area, "near the cylinder port that was closest to the firewall on the passanger side", not spraying it at the "top of the motor"!


try blowing smoke at the motor???
Please send me some of what you use -- I would like to try it.

[David T]

A second or third look can't hurt, especially if you are not sure what you are looking for. Unusual for a vacuum leak to be between the intake manifold and the head. I have found weird ones though. On one car someone had drilled through the bolt holes for the air cleaner and one of the bolts was not installed and it was a large leak. On one car the owner didn't know there was supposed to be a plug over the mixture screw. On another someone put a bolt that was too long at the front of the intake manifold and crushed the plug on the front making a big leak. Looking closely you might find some of them but using a smoke machine does it much easier and quicker. On another car I smoked at a tech session we saw smoke pouring out of the left pontoon. The most common leaks were:
Injector seals
The "O" ring seal for the air tube for the idle motor coming out of the bottom of the mixture unit
Dip stick seal
The top of the idle motor
Even a trickle of water isn't a great idea and you could still get some into the wells. Ether isn't a good choice either, it is VERY flammable. There are not many places for vacuum leaks towards the rear of the motor, there is the vacuum port underneath the throttle unit and the W pipe and it's connections. Could be missing an "O" ring or a spacer where it connects to the throttle unit. A smoke machine saves disassembly just to see if it is leaking.
David Teitelbaum

[DMC3165]

Even Grady is stumped at this point as to what's going on with this thing. In all fairness to him he knows I'm on a budget and I'm currently using the car as a DD so getting really involved in this and letting him tear it down is out of the question at the moment. So I'm left taking pot shots at it hoping I figure it out or wait until it's completely unusable then letting Grady do his thing.

What I can say is after Rob adjusted the timing and the mixture. All the hot start issues went away. However the cold start issues got worse much worse stranding me twice. The first time I was able to get the car going again by giving it a shot of ether. The second which happened Friday left me completely stranded. It turned out to be a weak fuel pump. It was overworked last year when I had a clogged pickup screen and ran it that way for about a month or so. So after changing the pump a lot of the issues went away. But it still idles low when cold (around 600) for a few minutes until it warms up but no more missing. So I'm thinking I've got several problems that were going wrong at the same time. The motor was racing a little when I sprayed ether by the intake port. But those gaskets are less then 2 years old and I can't believe they've failed already. Maybe a WUR problem also? As far as I know that has never been touched.

[Ron]

Has the CO/dwell been checked since the fuel pump (or anything else) was replaced? If not, that is probably the problem.
Has anything else you haven't mentioned been done to it (no matter how unimportant it might seem)?

If you didn't allow ether to get around the metering plate while testing, you have a vacuum leak since it revved and you must find and fix it.

[DMC3165]

I was spraying the the port on the manifold with ether. But the air cleaner assembly was still on the engine and it's possible some over spray crept in through the air cleaner or sonewher else. I like the idea of the smoke machine but I have no access to anything like that and I just quit smoking 2 months ago. So the cigarette option is definitely out. Between the car and a cigarette I'm guaranteed to go back smoking.

The AFR has not been adjusted since the new pump was installed Friday. I can't think of anything else since these problems started a month or so ago. Last year I changed the coil and ballast resistor the year before all the other tune up components were replaced. That's about it.

[Ron]

Then, in any case, you need to reset the CO!
No two pumps work the same (This is not a "splitting hairs" type of thing -- a new pump will almost always change the fuel delivery -- the PPR & WUR control the pressure(s), BUT there has to be enough of it and fairly consistent ).
I would not be surprised that the pump going out has been the problem(s) all along...

[DMC3165]

Ok so without having Ã* dwell meter can I (or should I) attempt to make minor adjustments to the mixture? Or just leave it until someone who had the tools and the know how can adjust it.

[Ron]

I'd recommend waiting...it is very touchy and people don't have much luck turning it a little thinking they can always put it back where they found it. (But honestly, if I had a backup ride, I'd be an idiot and try it anyway if it were me LOL)

EDIT: Wait...Can't you borrow a meter and Allen Wrench from AZ or O'Reilly's?? It's simple to do.

[David T]

I doubt changing the fuel pump is going to have any effect on the mixture, the PPR is supposed to adjust for changes in delivery pressure. If Rob didn't see it, it is not going to be something obvious or easy to find. I would not say he is "stumped", it is just you didn't want to pay for the time it would take for him to find the problem. As I said in a previous post, some things are just hard to find like blind holes no longer blind. If you want to take a trip to NJ I would "smoke" your car for you. Glad to hear you quit smoking! Maybe I could help you out on the summer fun run?
David Teitelbaum

[DMC3165]

I doubt changing the fuel pump is going to have any effect on the mixture, the PPR is supposed to adjust for changes in delivery pressure. If Rob didn't see it, it is not going to be something obvious or easy to find. I would not say he is "stumped", it is just you didn't want to pay for the time it would take for him to find the problem. As I said in a previous post, some things are just hard to find like blind holes no longer blind. If you want to take a trip to NJ I would "smoke" your car for you. Glad to hear you quit smoking! Maybe I can help you out on the summer fun run?
David Teitelbaum

I might take you up on this David. 3165 is going back to Grady's before the SFR to take care of my leaky clutch master. If he has the time I may ask him to mess with the idle and mixture unit one more time. I try to do as much of the maintenance myself as possible mainly for budgetary reasons but I know my limits and have tried to cheap out on a few things here and there in the past only to have it cost triple to repair the right way in the end. As I said it was me that held him back from getting too involved just so I don't tie up the car while I need it (my wife's car is still down with a blown head gasket. Never do a head gasket on a land rover yourself!!!!! Whole other story) Either way I plan to keep posting about this until I get it fixed. It may help someone else out in the future :)

[Ron]

I doubt changing the fuel pump is going to have any effect on the mixture, the PPR is supposed to adjust for changes in delivery pressure. If Rob didn't see it, it is not going to be something obvious or easy to find. I would not say he is "stumped", it is just you didn't want to pay for the time it would take for him to find the problem. As I said in a previous post, some things are just hard to find like blind holes no longer blind. If you want to take a trip to NJ I would "smoke" your car for you. Glad to hear you quit smoking! Maybe I could help you out on the summer fun run?
David TeitelbaumThe PPR can only change the pressure by bleeding off extra...it has no way to compensate for weak/borderline pressure due to a pump on its way out...nor would there be anything for Rob to notice WRT the pump if it was acting correctly at the time (and that's given he even had the opportunity to check it out)...it failed afterwards as I read it all anyways.