any clues? faulty something...

[arana]

Hi, greetings from Peru. I'm a new guy for this forum, so sorry for asking for advice on my first post, but this is driving me insane.

For background, the spider is an '81 2000, that the former owner replaced the injection system with a carb when he was having problems (you can't find parts here). I've been driving it on a daily basis for the last few years after an engine rebuild and it's been running great.

The car starts fine, sounds great, runs great, but sometimes, and not always, it feels like it starts to skip a little, gradually at first, but it eventually gets to the point that the car lurches and dies. If I turn off the key and then restart it immediately, it runs great as if nothing had happened.

This skipping/lurching can happen when the car is cold or hot, going uphill or downhill, accelerating or slowing down... basically whenever. Some days it doesn't happen at all and some days it happens 3 or 4 times. When it starts to happen, if I leave it on idle, it will run forever, but as soon as I press the accelerator, it goes through it's dying routine. My only option is to turn it off, then turn it back on and it runs perfect.

I've taken it in to a several mechanics and nobody can figure it out. I've rebuilt the carburetor, changed the fuel filter, checked the fuel pump, and all the lines but it didn't fix the problem, so I then thought it was an electrical problem. I changed the distributor, wires, coil, and lots of other things I don't know the english names for, but it still has the same problem. One thing I did notice though was that after changing the coil, the problem seems to happen with less frequency and the process from slight skipping to dead takes longer.

Apologies for rambling and asking a question on my first post, but I'm desperate. Any clues?

Araña
'81 spider 2000
Lima, Perú

[mbouse]

hello and welcome to the site.

you checked the fuel pump, but have you replaced it? is it still the electrical f.i. pump? i'll defer to a carb expert, but i suggest that unless it is a low pressure pump, or the mechanical pump intended for carburetors... your fuel pressure may be causing some issues.

also, have you checked the filter on the pickup tube inside the fuel tank? for that matter, are you confident the fuel tank is clean of debris?

a lurching sounds to me like a fuel delivery issue, not electrical.

[So Cal Mark]

replace the ignition module, and inspect the distributor pickup wiring

[pooldoctorstl]

I know I am new here, but I can't help myself....I love this stuff.

Mike and Mark are right but I have another suggestion. If it is still running the electric pump the PO may have installed a fuel pressure regulator to lower the pressure for the carb. If it doesn't have one and is running the original electric high pressure pump, it probably needs one. It could also be the problem. How did they "check" the pump? Try getting a fuel pressure gauge and hooking it up in line before the carb with enough hose to have it where you can see it with the hood closed and drive it untill it acts up. When it acts up see what the pressure is. If it is normal for the setup you have, you know the problem is not fuel delivery related. If it drops, start checking to see why. This could be a problem with either a mechanical or electric pump.

By the way, what happened to the old fuel injection system? Still have it?

Keep us posted.

Jeff

[Kevin1]

Have you noticed the tach acting up at the same time the car starts to misfire?
First thing I would try is replacing the distrubutor pick-up. They don't last all that long due to heat, and are quite often to blame for the symptoms you describe.

[armchairmechanic]

I can't help with your problem but I wanted to point out to those who don't know Spanish that arana (should have a tilde over the n) means spider in Spanish. Anyway, buena suerte!
George

[rlux4]

George, you've answered a question I've had for years, and no one knew the name of the wavy line over the Spanish n.
Thanks!
Ron

[LE759]

Kevin1, what does it mean when your tach starts to go crazy when the car starts to miss?
My car has been in the shop for a week and stil haven't found the problem.

Thank you
Stacey

[So Cal Mark]

it could mean an ignition fault, or it could be a tach with a short circuit. If it's been a week, try disconnecting the tach and see if the problem clears up

[LE759]

Mark are you saying a bad tach can cause the misfiring?

[majicwrench]

From my point of view, if a shop has had the car for a week, and still "can't find the problem" they either are not looking very hard or they are not very competent.

OR the car is in the shop and it is running perfectly, which is alway frustrating for all parties concerned. If the car consistantly runs poorly, and they can't find the problem in a week....go elsewhere.



Just my ramblings,
Keith

[So Cal Mark]

a faulty tach can cause ignition failure

[arana]

Regarding araña, I tried to have my user name with the tilde (ñ), but this forum only accepts regular english characters in the user name, so I had to settle for arana.

To answer some of the other questions, the tachometer never seems to act strange when the car is having the problem and I had already changed the ignition module. For the fuel pump, it is mechanical, not electrical, and I took it to a fuel pump specialist. Regarding the specialist, during the military rule years and up through the 1980s, nothing was allowed to be imported to Peru, so everything had to be rebuilt and people specialized in various specific parts. Depending on the part, a specialist can take it apart and put it back together blind folded with one hand and most times it is better than a new replacement part, so I'm not worried there.

I did recently clean the fuel tank and there was lots of garbage in it. My friends think the garbage in the tank was the problem, but I did have one die routine this morning. It could have been some of the junk still in the lines, but I'm not convinced.

For the old injection system, I don't know what happened to it. When I bought the car about 4 years ago, it was already gone, as were most things on the car. It took me a year of gathering parts to get it back on the road and after a complete engine rebuild it's been running great for the last few years with the existing carb, etc. I would like to go back to original injection eventually, but getting the parts is difficult.

I tried a place in the USA on the internet (Obert), but they said it would be too expensive and nearly impossible to gather up every single part and bolt for a complete system. I did ship some cosmetic things for the car from Europe a couple of years ago, but the shipping and import taxes were almost double the cost of the part, so that is out. There is a Russian car called Lada and during the communist years in Peru, they shipped lots of Ladas here. Well coincidentally, Fiat built the Lada factory in Russia and a lot of the parts are inter changeable. I have a few Lada parts on the spider, but since Lada didn't have injected cars, I'm out of luck for that.

Thanks for the responses and if and when I ever figure this out, I'll be sure to let you know.
Thanks

[pooldoctorstl]

When the engine dies, what exactly does it do? Does it act like it is running out of gas and surge some or does it just quit like you turned the key off? If it is running out of gas, you could be on to something with the junk in the fuel tank. How did you clean the tank? They have baffles in them so it's tough to clean them out and get everything. If there is still rust in it it could be clogging the pickup and causing the car to literally run out of gas. When it dies, the suction on the pickup in the tank stops and whatever was clogging it falls off, only to get picked up later on down the road and it all happens again. I don't know about Peru, but most radiator shops can boil out the tank and coat it inside to prevent rust from returning. Maybe some others here can tell you what they have done to their tanks, short of just buying a new one. But before you throw a lot of money at it, I would still try to hook up a fuel pressure gauge that you can see when it dies. Then you would know for sure if the problem is fuel or ignition related. Rather than replace parts one at a time, eliminate the good parts one at a time.

Good luck,
Jeff

[So Cal Mark]

has the carb been disassembled and cleaned since you found the debris in the tank? If not, the float bowl will have the same debris in it