important Jeep help needed please !

[rampant rivet]

Well would you believe it, just got my mates jeep sorted ready for Normandy and it starts playing up. It starts ok when cold and ticks over nicely then after a drive around the block it starts to run roughly on tick over and will not start very well when hot :mad:

We have changed the coil, condenser, rotor and plugs compression is good and its still not happy I'm thinking of fitting my carb from my GPW on it to see if that makes a difference or could it be fuel pump any advise much appreciated as the clock is ticking :nut: and if we cannot fix it I'll have to take my GP which will upset my mate who's 70 and was really looking forward to making this trip in his own vehicle.

 

Regards a frustrated Rivet

[Tony B]

Are any fuel pipes getting hot?

[Austin]

Tight valve clearances perhaps?

[Degsy]

Start from basics, check spark at plugs, both when hot and cold, if spark reduced when hot the obvious would be condenser, not uncommon for new one's to be faulty. Another possibility would be plug leads especially if you have modern type leads fitted. To check fuel supply remove inlet connection at carb to check flow from pump but catch the petrol in a container, you don't want it splashing on a hot manifold. Hope this is some help to you.

[Gordon_M]

Change the condenser again, there are a LOT of bad condensers out there, even new out of the box. It is even typical that it is OK when cold but starts to malfunction when it warms up, so don't believe any test instruments unless you heat the condenser up first.

[Pete Ashby]

A few questions to try to narrow down the issues:

 

1 Did it run ok before you overhauled it

 

2 What temperature are you seeing when it starts to run rough

 

3 What valve clearance have you set

 

4 Have you sprayed something like easy start or WD40 round the carb base and inlet manifold/block joints while the engine is running...... do you hear a difference in engine note, this will indicate an air leak

 

5 Have you done an vacuum test if so what results did you get

 

6 Have got a glass top to your petrol pump if so can you see the fuel boiling or air bubbles

 

7 Is your carburetor pre heater flap stuck open

 

8 What is your point gap setting

 

9 What value are your compression tests for each cylinder are they done hot, cold, or with oil down the bores

 

10 Is your float level set too high, when it's running rough are getting black smoke at the exhaust

 

11 have you changed the distributor cap

 

12 Are the plug leads breaking down/shorting out

 

 

That will do for starters, try to answer the questions and it may help to narrow down what the causes may be and help forum members to suggest a solution for you

 

Pete

Edited May 17, 2014 by Pete Ashby

[rampant rivet]

A few questions to try to narrow down the issues:

 

1 Did it run ok before you overhauled it YES

 

2 What temperature are you seeing when it starts to run rough ?? will see tomo

 

3 What valve clearance have you set Checking those tomo

 

4 Have you sprayed something like easy start or WD40 round the carb base and inlet manifold/block joints while the engine is running...... do you hear a difference in engine note, this will indicate an air leak Will try that tomo

 

5 Have you done an vacuum test if so what results did you get ??

 

6 Have got a glass top to your petrol pump if so can you see the fuel boiling or air bubbles Will fit my spare rebuilt one tomo

 

7 Is your carburetor pre heater flap stuck open ?? Think spring is weak bought a "new" one only to find it did not work when heated in others words not a bi metal type just a cheap repro :mad:

 

8 What is your point gap setting ??

 

9 What value are your compression tests for each cylinder are they done hot, cold, or with oil down the bores ?? Not present today when tested

 

10 Is your float level set too high, when it's running rough are getting black smoke at the exhaust Will check tomo doesn't smell or look like its rich.

 

11 have you changed the distributor cap On the list Tomo.

 

12 Are the plug leads breaking down/shorting out will replace tomo along with caps

 

 

That will do for starters, try to answer the questions and it may help to narrow down what the causes may be and help forum members to suggest a solution for you

 

Pete

 

Thanks Pete am going to have another session tomo afty I think its a case of elimination, Jeep ran fine before we replaced a blowing exhaust manifold gasket, I wonder if some sediment in the carb is causing the trouble ???

[rampant rivet]

Change the condenser again, there are a LOT of bad condensers out there, even new out of the box. It is even typical that it is OK when cold but starts to malfunction when it warms up, so don't believe any test instruments unless you heat the condenser up first.

 

Thanks yes will try another just in case

[Tony B]

Did you put any heat sheilds back after changing the manifold? Could hot exhaust be leaking onto the carb? Must be a trick to check for leacks. Been out with my Dodge today, was getting very warm and definite stubborn restart after stop start in show ring.

Edited May 17, 2014 by Tony B

[Pete Ashby]

Jeep ran fine before we replaced a blowing exhaust manifold gasket, I wonder if some sediment in the carb is causing the trouble ???

 

I don't think that it's sediment in the carb, if it was it would not be temperature dependent, you would be having the problem all the time if it was a blocked jet or intermittently if something was floating about in the float chamber. I would look first for an ignition based problem then when your certain it's nothing in that area go for a air leak/valve related issue, worst case is a head gasket blow between cylinders that's what the vacuum test would show up.

 

One more question.... the carb... is it a Carter or a Solex?

 

one more thing to check..... is the choke coming off fully, just because you push the button in on the dash doesn't mean that the butterfly is opening fully....could be a inner cable adjustment issue or the outer armored cable is not clamped properly so it moves forward and prevents the choke opening fully, take the air horn off and check that the butterfly is vertical when the choke knob is fully pushed in.

 

Good luck come back to the forum with the results and I'm sure people will help you.

 

Pete

[rampant rivet]

I don't think that it's sediment in the carb, if it was it would not be temperature dependent, you would be having the problem all the time if it was a blocked jet or intermittently if something was floating about in the float chamber. I would look first for an ignition based problem then when your certain it's nothing in that area go for a air leak/valve related issue, worst case is a head gasket blow between cylinders that's what the vacuum test would show up.

 

One more question.... the carb... is it a Carter or a Solex?

 

one more thing to check..... is the choke coming off fully, just because you push the button in on the dash doesn't mean that the butterfly is opening fully....could be a inner cable adjustment issue or the outer armored cable is not clamped properly so it moves forward and prevents the choke opening fully, take the air horn off and check that the butterfly is vertical when the choke knob is fully pushed in.

 

Good luck come back to the forum with the results and I'm sure people will help you.

 

Pete

 

 

Thanks Pete good advice I'm hopefull we can resolve this issue soon :nut:

[commander]

I se you have fitted a new coil is it the correct one jeeps need the old fashioned coil

not the coils fitted to modern cars they will work but not very efficiently also when it

starts to play up feel the coil if it is warm/hot it is knackered

Commander

[arcot1751]

I se you have fitted a new coil is it the correct one jeeps need the old fashioned coil

not the coils fitted to modern cars they will work but not very efficiently also when it

starts to play up feel the coil if it is warm/hot it is knackered

Commander

 

I had the same problem with my GPW during refurbishment we changed the coil to a new one, the jeep ran like a clock, hot and cold but was very difficult to restart once hot, I tried timing, carb, valve clearances. air leaks etc. I thought it was maybe fuel vaporisation and lived with it for a while. Last winter I decided to get it sorted once and for all I thought back to all we changed during the refurbishment and remembered the coil so I dug the original out and refitted it and hey presto the jeep runs perfectly I even realised it runs better at all temperatures than it did with the new coil fitted. Just because an items new doesn't mean it's ok same goes for condensers there are many faulty batches out there.

[rampant rivet]

Just spent another three frustrating hours trying to sort jeep but no luck, have replaced old ht leads and cap checked points gap ok, checked tappets all ok replaced carter carb with my spare no improvement, am going to fit my SPARE REBUILT FUEL PUMP TOMO EVE BUT TO BE HONEST I AM RUNNING OUT OF IDEAS AS TO WHAT SHOULD BE CAUSING THIS PROBLEM.

The thing starts when cool and ticks over ok running sweetly, but the moment you drive it down the road it all goes pete tonge with the engine running roughly and spluttering on tickover GRRRRR !

[Pete Ashby]

If you are certain it's not ignition related I would seriously recommend putting a vacuum gauge onto the PCV port of the inlet manifold around £14 to £20 on e bay next day delivery.

If you haven't used a vacuum gauge before for engine diagnostics (sorry if I'm telling you how to suck eggs) google 'reading a vacuum gauge' there are some excellent sites that explain how to interpret what the gauge is telling you.

 

Pete

[Richard Farrant]

I have been reading through all this and as I see it, this only happened after changing a manifold gasket. So rather than going chasing other theories, the best thing is to relook at this. Did you put a straight edge along the manifolds to check for bow before refitting. the other point I picked up was you said that you went to replace the bimetal spring on manifold heat flap and it did not work. So two questions regarding this, was it fitted the correct way around? And is it being held in the pre-heat position all the time?

 

cheers Richard

[T corbin]

Have you tried connecting the ht leads direct to the plugs without the suppressor caps . I had some nos caps that where breaking down when hot. Connected the leads direct to the plugs . All ok T CORBIN

[rampant rivet]

If you are certain it's not ignition related I would seriously recommend putting a vacuum gauge onto the PCV port of the inlet manifold around £14 to £20 on e bay next day delivery.

If you haven't used a vacuum gauge before for engine diagnostics (sorry if I'm telling you how to suck eggs) google 'reading a vacuum gauge' there are some excellent sites that explain how to interpret what the gauge is telling you.

 

Pete

 

Thanks Pete will check that out over the next few days

[rampant rivet]

I have been reading through all this and as I see it, this only happened after changing a manifold gasket. So rather than going chasing other theories, the best thing is to relook at this. Did you put a straight edge along the manifolds to check for bow before refitting. the other point I picked up was you said that you went to replace the bimetal spring on manifold heat flap and it did not work. So two questions regarding this, was it fitted the correct way around? And is it being held in the pre-heat position all the time?

 

cheers Richard

 

Hi Richard have been trying to think it through since replacing the gasket, when we checked the faces with a straight edge they were all over the place so had them milled nice and flat to help the gasket seal properly, it could be that the flap is in the wrong pos will have another look tomo I think you may be correct in that something has occurred during the gasket replacement, the new spring we tried to fit would not react when hot even when warmed a bit by a blow lamp so the original was put back on which sems to work ok.

Edited May 19, 2014 by rampant rivet

[rampant rivet]

Have you tried connecting the ht leads direct to the plugs without the suppressor caps . I had some nos caps that where breaking down when hot. Connected the leads direct to the plugs . All ok T CORBIN

 

new dizzy cap, leads and spark plug caps fitted made no difference

[Richard Farrant]

Hi Richard have been trying to think it through since replacing the gasket, when we checked the faces with a straight edge they were all over the place so had the milled nice and flat to help the gasket seal properly, it could be that the flap is in the wrong pos will have another look tomo I think you may be correct in that something has occurred during the gasket replacement, the new spring we tried to fit would not react when hot even when warmed a bit by a blow lamp so the original was put back on which sems to work ok.

 

If the manifolds were separated and machined separately, maybe they were not correctly aligned on refitting. Sometimes it is necessary to file the holes out a little where they clamp together in order for faces to align after machining. My bet is the problem is in this area somewhere.

[rampant rivet]

Hi Richard unit was machined as one as splitting risked a bolt shearing off , face of manifold was good and true when refitted with no cracks

[Richard Farrant]

Hi Richard unit was machined as one as splitting risked a bolt shearing off , face of manifold was good and true when refitted with no cracks

 

That probably rules that out then. I would still check the flap in case the spring is wrong way around or flap sticking.

[GeePig]

I agree with Richard - check that flap.

 

Are all the heat shields in position, including on the radiator, and the fuel pipe routed correctly? Is the coolant level in the radiator still OK?. Have you got your mate to press a balled up cloth onto the exhaust outlet while you listen for any blowing joints on the exhaust and manifold?

 

trevor

[rampant rivet]

Thanks again for advice I've had to take a night off this problem but will be back on it tomo eve, I think you're right it is probably a manifold problem I did think maybe it was the crankcase valve but that was cleaned and put back together without improving anything, I think the manifold will come back off to check for any cracks tomo, if we don't sort this soon I'll have to dig my GPW out of my parents garage and we'll have to take that instead :nut:

[rampant rivet]

OK have just got back from working on Bills Jeep and ..................... ITS FIXED :-D :banana::-D We took the manifold back off to check inlet for cracks etc then put it all back together being very careful how it went together and it seems to be ok which is a great relief :cheesy: still not sure exactly what the cause was but am just glad Bill can get his Jeep to France, Many Many thanks for all your good sound advice but as Richard said it all stemmed from replacing the exhaust manifold gasket now I can get back to getting all the gear ready for our trip the bike trailers sorted apart from it now needs two new tyres so that on the list for Sat :-D

 

Cheers all RR.