[Laser Bob]

I have a very intermittent problem with losing power in my 83 Esprit. While driving along with interstate traffic (not hotdogging or racing) the car will start to lose power, miss, and RPMs slow down. Feathering the gas pedal doesn't help a lot. After turning the car off and letting it sit for awhile it will run fine for awhile. The car does not overheat. As it always is, every time my mechanics drive the car it doesn't happen to them.

My mechanic said he has seen this one other time- on a Toyota- where the cam belt actually gets hot and stretches enough to offset the timing a little. When it cools down, it goes back to normal.

I'm not a mechanic, but in theory it makes sense to me. Anyone else ever hear about this?

 

[G8nightman]

When is the last time you changed the belt?

 

[Gallagher]

Depending on how old your belt is, I would tend to look closer at the fuel system. I had a boat with a Chevy v8 that did almost the exact same thing. It was almost as is the crap would settle out of the filter to the bottom. When you ran it for a while it seemed as though maybe the crap made it's way back onto the filter media and blinded it...let it sit and the process repeated.

How old is the filter?

Not sure if the esprit suffers from vapor lock in the fuel lines, but the symptoms would be similar if that was occurring as well. Mustangs are famous for fuel line vapor locks on long highway trips...from experience. Stopping and letting it cool will cure a vapor lock.

 

[lotus4s]

I wouldn't say it's impossible but I think if you're timing belt stretched enough to affect the timing that much you would more than likely have lost the belt by now or it would have at least skipped a couple of teeth and suffered some catastrophic failure.

As was asked, how old is the belt and is it the correct belt and name brand?

I've heard of others with similar intermittent symptoms due to a bad pick-up wire in the distributor or something of that nature. My knowledge of the mechanical ignition systems is limited, maybe one of our gurus will chime in...

 

[esprit888]

I have a very intermittent problem with losing power in my 83 Esprit. While driving along with interstate traffic (not hotdogging or racing) the car will start to lose power, miss, and RPMs slow down. Feathering the gas pedal doesn't help a lot. After turning the car off and letting it sit for awhile it will run fine for awhile. The car does not overheat. As it always is, every time my mechanics drive the car it doesn't happen to them.

My mechanic said he has seen this one other time- on a Toyota- where the cam belt actually gets hot and stretches enough to offset the timing a little. When it cools down, it goes back to normal.

I'm not a mechanic, but in theory it makes sense to me. Anyone else ever hear about this?

Check your distributor pick up coil/wires, common that they start to fail gradually, but not completely due to the constant working of the wires during mechanical and vacuum advance. Does this typically happen at the same RPM ?

 

[mieczkow]

I'm with Jim K. on this issue. I don't think a stretched cam belt makes a lot of sense. First of all it would take several hours for the belt to reach ambient temperature after a drive, so shutting it off for a short duration I don't think would allow a belt to "contract". It just does not make a lot of sense that the belt could stretch that much without some REAL serious issues - like banging into valves or just jumping off the sprockets. It would look really closely at your fuel system.

 

[David Craig]

I had similar symptoms on an 86 Corolla.

One time it was due to a dirty fuel filter. I needed to replace it after about 80,000 km. The car ran perfectly after that.

Another time (in rain) it was due to a rubber seal around the distributor cap. The seal had stretched over time and was no longer water tight. The car would stall out in rain but be OK after about 10 minutes if I stopped at the side of the road.

 

[Laser Bob]

Thanks for the inputs. I purposely left out some of the qualifiers because if I mentioned anything about belt age everyone would jump on the 'change the belt' bandwagon without considering whether the original question was plausible. Thanks Lotus4s for at least saying it's possible. Stranger things have happened.

We've been working on this problem for awhile. New fuel pump, new fuel filters X3, new plugs, wires, coil, rotor & distributor cap.

I have receipts showing the belts were replaced in 2007 and new belts for everything were purchased in 2011. I have no info on what make or model the new belt is, the receipt just says "timing belt...$109".

 

[Beerman]

I would get a new mechanic.

Any mechanic who says a modern timing belt stretches enough to affect the performance isn't any mechanic at all. No way.

Most of these timing belts have fibers like kevlar in them. Essentially, kevlar does not stretch. Not at all. That's why it's used in grand prix sailboat running rigging and sails. It just doesn't stetch, but it stays flexible.

You have some running problem not related to the timing belt.... I'd look at the ignition components first and make sure everything is good, then I'd look at all the fuel system components, then I'd check for loose grounds and weak wiring associated with any engine components.

You can forget about your timing belt.

 

[carbuff]

You say your coil is new...is it a direct replacement? Does it feel really hot when the car loses power? (Run with the cover off the relay box. Put your hand on the coil. If it HURTS or turns your skin red, you may have the wrong coil for your ignition system.)

Still have the Lucas High-Energy ignition, or have you gone to a Pertronix or equivalent? I know Pertronix has different resistance coils for different applications.


And the Lucas black box (amplifier) is a GM part, remember the piece that fit into the dizzy cap on GM cars? They could be affected by heat also. (Plus, make sure the one bolt on this unit, through which the ground for the relay/coil box travels, is connected tightly and clean).




I don't think it's your timing belt either...TBs are CREATED to maintain length, and it will, unless it un-ravels...and then you would be asking us about what kind of valves and pistons work best! anic:

 

[Laser Bob]

Pertronix ignition was installed before my ownership. Replaced the old coil (forgot the name & the car is in the shop) with the same make, model, ohms.

 

[carbuff]

I'd call JAE and ask if Pertronix units for Esprits ever fail.

With the original pickups, the tach goes all wonky [<--- Technical Term] if the pickup or the wire starts to fail.

I know that a few years ago (10?) the dizzy rotors available then were prone to failure...arcing to the center of the dizzy instead of passing the spark to the wires.


+++++

And like Beerman said, if ignition checks out, look to fuel. Specifically, fuel pressure...ISTR something (fuel regulator?) on the Carb turbos that could fail. Maybe Cal H could ask Tim E (Esprit2) to weigh in. He would know the specs.
:bow:

 

[amanda11270]

My 88 was starting to miss when it would get hot due to the spark plugs overheating, It was driving me bonkers diagnosing it. When you car starts to miss, stop, put a timing light on it, and check every cylinder, the light will not flash when the miss occurs if its your plugs. I took my timing light with me on a drive to find this problem, then immediately stopped to check all the plugs with the light when it occurred. I changed everything before discovering it was my plugs, Pertronix, wires, coil, cap, fuel filter, fuel accumulator, sensors, vacuum hoses, warm up regulator, cleaned fuel injectors, relays, everything friggin thing.

I had to install I think, BPR8ES plugs I believe it was, and it solved my problems. Which ever number plug it was, it was one colder than recommmended for the 88 Esprit. Dont know why it would overheat the recommended plugs, but that was like almost 3 years ago and its been fine since.

I've never heard of a timing belt stretching, but I guess anything is possilble. You would think if it stretched it was too tight to begin with.

One thing about this experience, many of my engine components are still practically new now, and I have the old ones as spares.

 

[jtrealty]

Stretchy timing belts may occur on a Toyota but it doesn't happen on a Lotus. It is an ignition or fuel problem. Looks like your mechanic is trying to "shotgun" the problem by buying the parts store one part at a time at your expense till he "gets lucky". Go to someone who can diagnose the problem more accurately. By changing all of this stuff you actually introduce more problems since you may put a bad part in or a good part badly causing even more issues.
David Teitelbaum

 

[89.5 Esprit SE]

Loose yes, stretchy to the degree you suggest....no way!
Having a carbureted car makes your symptoms pretty normal, teasing out the cause may be a little time consuming

 

[lotusdriver2001]

On a 4 cylinder Lotus I believe the belt should get tighter as the engine warms due to thermal expansion of the engine. That is why there is a specific temperature range for tensioning the belt. You can't just wait a couple of hours after driving, it's overnight.

 

[firefighter1c57]

I've had older cars with similar problems, it's usually fire related, IE coils overheat, plugs overheat, bad CDI, or points depending on the system, and yes, I've bought brand new electrical parts from stores, installed them, and had them be bad out of the box.

On thing I will ask though, when was the last time the valves were adjusted? It's very rare, but on bikes, which have very tight valve clearance as well, if they are way out of spec, it will cause a miss to when everything heats up.

 

[Laser Bob]

Thanks for all the input. I too thought the idea of a cam belt stretching a little bit was kinda weird, but I'm not a mechanic so I figured I'd at least ask. Weirder things have proven to be true.

I figured 1) the only stupid question is the one I don't ask; and 2) just in case this happened to have an element of truth to it, ignoring it could be very very costly.

 

[maxvelocity]

Hmmm...you live in FL. There are more than a few places to service an Esprit's down there. Maybe take it to an Esprit specialist. You have an early turbo car they are finicky and have their quirks. How many miles you got on the car?