weird startup issue

[Mrdashbo]

Ive had my car running ok for a while but it seems now when it starts cold it won't rev at all until warm. it almost like there is no choke. if i try to rev it dies instantly. my cold start injector, thermo time switch are both brand new. i suspected a bad fuel regulator connector as it been a bit loose in the past.

before i dive into looking at it i wondered if anyone else has seen this issue. its also been a tad and i do mean just a tad hard to start up. it cranks two or three times before it forces up which has never happened before. sometime on start up it dies right away (5 secs in ish)


i don't think its a fuel delivery issue because all; my fuel system is new from pump to meter head. I'm thinking electrical.

Mike

[David T]

Ive had my car running ok for a while but it seems now when it starts cold it won't rev at all until warm. it almost like there is no choke. if i try to rev it dies instantly. my cold start injector, thermo time switch are both brand new. i suspected a bad fuel regulator connector as it been a bit loose in the past.

before i dive into looking at it i wondered if anyone else has seen this issue. its also been a tad and i do mean just a tad hard to start up. it cranks two or three times before it forces up which has never happened before. sometime on start up it dies right away (5 secs in ish)


i don't think its a fuel delivery issue because all; my fuel system is new from pump to meter head. I'm thinking electrical.

Mike

If it runs well once it gets hot the problem is most likely the Control Pressure Regulator aka warm-up regulator. Check the vacuum hoses to it. If you can get your hands on a fuel pressure gauge you can verify control pressure. If it is high when cold the CPR is bad.

[Ron]

i suspected a bad fuel regulator connector as it been a bit loose in the past.

...

i don't think its a fuel delivery issue because all; my fuel system is new from pump to meter head. I'm thinking electrical.

Mike
+1 DT

yeah, tiny leaks muck it all up...I'd double check that connector then all of the basic settings: timing, ...CO last too/first.

[Mrdashbo]

ill check out the vacuum lines, i did have a quick look this afternoon and I've noticed a weird set up on the vacuum lines.

looking down on top of the engine, I have two outlets on the air inlet manifold. The left hand inlet goes directly to the brake vacuum line, and the right hand one has a bolt stuck in it?? So thats a bit of a weird situation, according to my manual (AND I MAY HAVE THIS WRONG) the left side should go to the brake vacuum but also T off to the aircon heater vacuum. But I cannot find for the life of me what the right hand side one should go to? Does this affect running too? or is it only the small vacuum lines to the pressure regulator that affects running. so i suppose what I'm asking is does anyone have a drawing of the routing of both sides, my manual is somewhat crappy

I hope that makes sense.

[sdg3205]

Whaaaaaa?!

I'm nowhere near my car but IIRC the left plenum nipple supplies vacuum to the y-pipe thermistor and the right plenum supplies vacuum to the booster.

[Ryan S.]

Detail photos would be helpful.

[Mrdashbo]

Whaaaaaa?!

I'm nowhere near my car but IIRC the left plenum nipple supplies vacuum to the y-pipe thermistor and the right plenum supplies vacuum to the booster.

Yes that's the part that is all ok all the correct lines are going to the idle thermistor. But above the nipple that leads to the y pipe on the manifold there is another larger nipple (LHS) that is currently leading to the brake vacuum and the right side has the bolt in it.

Mike

[sdg3205]

Let's see a picture. I guess vacuum is vacuum!

[Rich]

ill check out the vacuum lines, i did have a quick look this afternoon and I've noticed a weird set up on the vacuum lines.

looking down on top of the engine, I have two outlets on the air inlet manifold. The left hand inlet goes directly to the brake vacuum line, and the right hand one has a bolt stuck in it?? So thats a bit of a weird situation, according to my manual (AND I MAY HAVE THIS WRONG) the left side should go to the brake vacuum but also T off to the aircon heater vacuum. But I cannot find for the life of me what the right hand side one should go to? Does this affect running too? or is it only the small vacuum lines to the pressure regulator that affects running. so i suppose what I'm asking is does anyone have a drawing of the routing of both sides.....

About the vac hose routing info does your D have a Vacuum Hose Routing label on the underside of the engine cover? If so then start with that.

Also, if your car ever did run well during warmup with the hoses routed the way they are now then it's likely they were/are routed OK and that you now have a vac leak somewhere in the ones that are in the WUR/CPR circuit.

Our car had a less severe version of the stumbling-when-cold symptom you describe - it disappeared after I replaced one of the original vac hoses which developed a small crack in it at the tee fitting closest to the WUR.

[Jonathan]

You're talking about the vacuum connections/nipples on the backside (towards the front of the car) of the intake manifold, right?

Mind the mess, my intake is out of the car right now and it hasn't had it's bath yet...

38821

I think you're talking about these connections?

The connection you see that still has a chunk of hose on it (cut off to remove intake as it was not in the mood to budge), is on the "passenger" side of the car (RH and LH seems to get confusing back here), and this is the short (even shorter now!) piece of vacuum hose that connects to the "tee" fitting that runs with the heater valve. I would say that nipple is about 1/2" in size approximately.

There is another, similar 1/2" size nipple connection on the "driver's" side of the intake, which you can see in the photo and which does not have any chunk of hose still on it. Now, when you mentioned it going all the way up to the brake booster, you got me skeptical of my own explanation, and I may need to go out and double check on my own car, but this second larger port on my car connects down to the vacuum modulator that is part of the automatic transmission.

(On a side note, my car's vacuum connections might not be as intended by the factory, as the how-to guide for removing the intake didn't mention a 3rd nipple on the back of the intake and mine definitely has three. This could be just because it differs from a manual trans set-up, not sure).

The small port above that one (still on the driver's side) is the one which connects directly with a small diameter hose (maybe 1/4" or thereabouts) and it is that hose which comes from the thermal control valve. That thermal control valve is the sensor which threads into the Y pipe in the valley and has three vacuum hose connections on it and no electrical connections. You can see it in an exploded view in the bottom corner of the vacuum routing label on the underside of your lower engine cover (which I've attached here since it sounds like you don't have one).

38822

When you mentioned a "bolt" in that backside of the intake, there are a couple "plugs" that are supposed to be there and there is also a grounding wire screw for the O2 (oxygen) sensor. It is generally located on the passenger side, and actually the "side" of the intake and not technically the "back". In my photo where you see the red wire and black electrical connector, that is what you should see on that grounding wire location, but mine got temporarily relocated to the snapped off chunk of air filter housing bolt where you see it. I need to remove that leftover chunk of bolt to get my final air filter housing bolt in and also drill out the chunk of screw left in the grounding hole (which you can't see here) to return it to it's intended configuration.

Hope that helps. I would guess you don't have your intake off and can't see the connections underneath it? I would recommend going easy on tugging or pulling on hoses or wiring harnesses while you look around as while most connections (vacuum or electrical) won't come right off super easily, they will come off if you pull hard enough on them. Just be conscious of what you are moving or pushing out of the way while trying to figure things out. And once finished, give things a final look-over to ensure you don't now have any wires or hoses hanging on or touching the exhaust piping (especially if you have an automatic).

[Mrdashbo]

You're talking about the vacuum connections/nipples on the backside (towards the front of the car) of the intake manifold, right?

Mind the mess, my intake is out of the car right now and it hasn't had it's bath yet...

38821

I think you're talking about these connections?

The connection you see that still has a chunk of hose on it (cut off to remove intake as it was not in the mood to budge), is on the "passenger" side of the car (RH and LH seems to get confusing back here), and this is the short (even shorter now!) piece of vacuum hose that connects to the "tee" fitting that runs with the heater valve. I would say that nipple is about 1/2" in size approximately.

There is another, similar 1/2" size nipple connection on the "driver's" side of the intake, which you can see in the photo and which does not have any chunk of hose still on it. Now, when you mentioned it going all the way up to the brake booster, you got me skeptical of my own explanation, and I may need to go out and double check on my own car, but this second larger port on my car connects down to the vacuum modulator that is part of the automatic transmission.

(On a side note, my car's vacuum connections might not be as intended by the factory, as the how-to guide for removing the intake didn't mention a 3rd nipple on the back of the intake and mine definitely has three. This could be just because it differs from a manual trans set-up, not sure).

The small port above that one (still on the driver's side) is the one which connects directly with a small diameter hose (maybe 1/4" or thereabouts) and it is that hose which comes from the thermal control valve. That thermal control valve is the sensor which threads into the Y pipe in the valley and has three vacuum hose connections on it and no electrical connections. You can see it in an exploded view in the bottom corner of the vacuum routing label on the underside of your lower engine cover (which I've attached here since it sounds like you don't have one).

38822

When you mentioned a "bolt" in that backside of the intake, there are a couple "plugs" that are supposed to be there and there is also a grounding wire screw for the O2 (oxygen) sensor. It is generally located on the passenger side, and actually the "side" of the intake and not technically the "back". In my photo where you see the red wire and black electrical connector, that is what you should see on that grounding wire location, but mine got temporarily relocated to the snapped off chunk of air filter housing bolt where you see it. I need to remove that leftover chunk of bolt to get my final air filter housing bolt in and also drill out the chunk of screw left in the grounding hole (which you can't see here) to return it to it's intended configuration.

Hope that helps. I would guess you don't have your intake off and can't see the connections underneath it? I would recommend going easy on tugging or pulling on hoses or wiring harnesses while you look around as while most connections (vacuum or electrical) won't come right off super easily, they will come off if you pull hard enough on them. Just be conscious of what you are moving or pushing out of the way while trying to figure things out. And once finished, give things a final look-over to ensure you don't now have any wires or hoses hanging on or touching the exhaust piping (especially if you have an automatic).



Ah right this does make a bit more sense,

The nipple with chunk of hose you have on the passenger side i have exactly the same BUT there is a bolt jammed in the end of the rubber hose plugging it, so it basically goes to knowhere.

The drivers side 1/2 " hose on my car is the one going to the brake booster. The smaller nipple above it is connected as it should be (exactly the same as the routing label you attached)

So my question to you would be, the 1/2" driver side nipple on your car, what did it go to? Do you have an Automatic? Mine is a 5 speed manual. If the 1/2" driver side nipple is supposed to go to the auto tranny what does it do for the manual? Does it need plugging or just leaving. i have a feeling this is the reason for my judder starting as there are no other vac leaks i can find.

Mike

[Jonathan]

Ah right this does make a bit more sense,

The nipple with chunk of hose you have on the passenger side i have exactly the same BUT there is a bolt jammed in the end of the rubber hose plugging it, so it basically goes to knowhere.

The drivers side 1/2 " hose on my car is the one going to the brake booster. The smaller nipple above it is connected as it should be (exactly the same as the routing label you attached)

So my question to you would be, the 1/2" driver side nipple on your car, what did it go to? Do you have an Automatic? Mine is a 5 speed manual. If the 1/2" driver side nipple is supposed to go to the auto tranny what does it do for the manual? Does it need plugging or just leaving. i have a feeling this is the reason for my judder starting as there are no other vac leaks i can find.

Mike

Makes me think that your hose with the bolt jammed in it (going nowhere) is what would have gone to the tee joint and that is where the one on the other side now goes. A picture of this hose and jammed bolt might help. I can't visualize that very well without thinking it would be leaking vacuum/air at least a little bit?

I'll have to try and double check where the brake booster vacuum comes from as I'm not sure right now. I hadn't thought it came directly with its own line, and came tee'd off a different line, but now I'm not sure and don't want to tell you the wrong thing until I'm sure.

I do have an automatic. I was under the impression only auto cars had this vacuum modulator line, but maybe not. Perhaps someone else will help and chime in with what the vacuum manifold taps are supposed to be doing and where the hoses are going.

[Ron]

Check out: #51 HERE (http://store.delorean.com/c-365-7-3-0-electricalmechanical-controls.aspx) and #26 HERE (http://store.delorean.com/c-275-2-4-0-evaporative-control-systems.aspx).

[Jonathan]

Nice one Ron. That #51 is the hose I sacrificed to the Valley Gods... and need a new one. Thanks for pointing it out.

Curious, for #27 here: http://store.delorean.com/c-293-4-5-6-computermodulator.aspx

(I don't know how you got the link to be within the #27 characters...)

Do you know where the intake/engine end of that #27 vacuum line for the automatics terminates... on a parts diagram that is?

[Ron]

Curious, for #27 here: http://store.delorean.com/c-293-4-5-6-computermodulator.aspx

(I don't know how you got the link to be within the #27 characters...)
I don't understand what you are asking??


Do you know where the intake/engine end of that #27 vacuum line for the automatics terminates... on a parts diagram that is?Not showing #27 itself...but:

#27 connects to #42, which is connected to #41 HERE (http://store.delorean.com/c-334-1-4-1-air-induction-system.aspx).
(Manuals plug the port with #40).

[Jonathan]

I don't understand what you are asking??

Not showing #27 itself...but:

#27 connects to #42, which is connected to #41 HERE (http://store.delorean.com/c-334-1-4-1-air-induction-system.aspx).
(Manuals plug the port with #40).

Thanks Ron. My plug and small port are installed opposite to what is shown. Makes no difference in vacuum, just that the plug is on the passenger side of the intake for me and the nipple is on the driver's side.

The part I was asking about you didn't understand wasn't car related, it was just wondering how you got a link to not show the actual letters and numbers of the link but instead showed words of your choosing... although as I'm looking at the part I am quoting from you, I can see the codes revealed and it looks like you just use a /URL type thing in brackets. Nothing important... as you were.

[Ron]

Ah. An easy way...

Copy the link address from a webpage/etc, type out what you want to be seen, highlight it, click icon circled in red:
38840

A window will appear:
38841

Paste link into URL box, click "OK".