1981 124 2000 FI hard starting problem- RESOLVED

[raysorm]

Hello I just purchased a 1981 FI 2000 that has hard starting problem - when I go to crank it seems like fuel starved and then if finally kicks in after a few tries. Runs rough Idle and wants to die. I give it some gas and slowly starts running to Idle Ok. Drives just fine and does not die on me. I can shut it off and start right back up after running. But if the cars sits for more than 5 minutes it will be hard start situation again. Not sure if this could be an ignition problem or a fuel injection problem?

[RRoller123]

Could be a whole bunch of things. Try checking the fuel pressure at the CSI, and it is always a god idea to send the injectors out for cleaning when getting a car with unknown service history.

There are a bunch of good FI manuals available:

Brad Artigue’s FI Guide is excellent, and is contained in his book; “Maintaining The Italian Roadster”.

For those interested in further studying the Bosch L-Jetronic system, there is an amazing amount of quality material available on the web. All these references below come up with a Google search on the term: “Bosch L-Jetronic”

This link from the BMW folks has a very good PowerPoint type presentation on the components, etc.

http://www.firstfives.org/faq/ljet/jetronic.pdf

This one, from the VW folks, has a good component description too, but also a good trouble shooting manual:

https://www.type4.org/manuals/ljet/

Here is Bosch's own manual, a long, detailed slog through the swamp for sure. Probably best printed out for studying. I think it is the best of the bunch for a complete in depth study of the system, as it includes selected engineering design data, explaining some of the design decisions they made.

http://foxed.ca/rx7manual/manuals/BOSCH ... Manual.pdf

[raysorm]

Thanks I am suspecting the fuel injectors - seen several videos that those years of the bosch injectors wear out and leak back when the engine is shut off and cause flood and vapor lock. Still collating

[gbraun]

It should be the starting injector (with the blue connector), I had the same problem on my spider. I clean it and with a bicycle pomp (petrol on the tube) and a battery I made few running and at least it worked again.

[raysorm]

You mean the Cold Start Fuel Injector with the blue connector? You disconnected and attached at tube with a bicycle pump and ran fuel through it? That cleaned it ? Did you mean get new battery. Thanks

[raysorm]

I have replaced the spark plugs - dist cap and rotor and checking all other ignition to make sure not an ignition prob and nothing new. Just received my shop manual and I see how to remove the injectors correctly. Just got and reviewing my Fuel Injection Diagnosis Guide for Fiat spiders and I am reviewing it to get more information before working on FI system to run this problem down. I will figure this out and update but all advise needed Thanks

[ORFORD2004]

For me it was the AFM.

[PhillySpider]

+1 on the AFM. I chased injectors, cold start valve, FI relay replaced and finally found the AFM flap was sticking. I had intermittent hard start problems follow by no start at all in the cold weather...

[raysorm]

AFM is air flow meter? You replaced it or cleaned it some how? please tell me more TY

[Spider951]

I also vote that it's likely the Air Flow Meter (AFM). My '81 was having similar symptoms when I bought the car (but got progressively much worse) - hard starting, having to feed it plenty of gas just to keep from stalling, ran OK once warmed up good, but turn it off, wait a few minutes and then have to restart the whole process over (a real pain if you just want to stop on the way home to pick up a loaf of bread!). I replaced cold start injector, aux. air valve, big air intake hose, cleaned out tons of gunk from crankcase oil vapor separator (I invented some new colorful words fitting those separator hoses), new coil, spark plugs, distrib cap, rotor, etc etc. All that helped some, but did not really fix the problem. I finally did some research on the AFM, opened the lid of the thing and saw the dreaded "double skid marks" on the carbon resistor, i.e. worn out AFM. The main fix was, therefore, a refurbished Air Flow Meter - instant change for the better. There are several good articles about AFM wear - most of them, though, from BMW, VW, Porsche, Alpha Romeo sites.

Steve

[RRoller123]

There has been a lot of discussion over the years on the AFM, how to open it and clean the TF resistor field, wiper, etc. A search here on the forum should come up with a lot of references. It would be worth going in there and cleaning it up and see if that helps!

There are professional rebuild services available, if a quick cleaning doesn't fix the problem. There is a point where the tracks are worn so deeply that they replace the TF resistor board, otherwise, bending the wiper arms to get them to ride on a fresh section seems to work. There is a detailed procedure here somewhere that shows how to do this.

Pete

[raysorm]

UPDATE - Ok been off this repair due to had to to major brake job first to make the Car safe. Ok so started off doing diagnostic on the ignition side. Found that the pick up coil wires were fried and the distributor trigger teeth have been damaged. Also the Ignition coil was checking out of specks. So Replaced the coil - module and distributor and learned how to time the engine with timing light which was cool to learn. But this did not solve the problem but was needed anyway. So now on the fuel injection side. Right off starting with checking the fuel pressure at start and running pressure for regulator. So Car started fine cold as normal and fuel pressures check good. But once hot shut the car off and the hard start or no start happened. The fuel pressure on trying to restart hot is now low at 22 to 25 psi with no start. Where at cold engine was in specs at 38 psi and engine started. When I did the cold start the engine purred like a kitten for 20 minutes with all the new ignition updates and tuning. So suspecting the fuel pump is going bad when gets warmed up and runs ok but will not provide enough pressure to restart when hot. Does this sound about right? Thanks

[courtenay]

That's what happened when my fuel pump went ('80 FI). Started cold fine and ran well for as long as I wanted it to - as long as I kept the idle up. Shut it off when hot and it wouldn't restart until it was cold again. Let the idle go down when hot and running and it would stall and not restart, again until it was cold. Replaced the fuel pump and all good.

[raysorm]

RESOLVED - For me turns out was the fuel pressure regulator was bad. When testing it was leaking and pumping fuel through the diaphragm to the vacuum side. Thinking was not letting hold pressure properly once the engine was hot. The spring may have been bad too. Car seems to start fine now when hot and left for a time. Had a tough time breaking it loose from the fuel line. Seems like either there was some Teflon tape or some sort of lock tight put on the threads that had petrified from the heat. I installed the new one with nothing as I read in many places not needed with a flare fitting and is holding fine with no leaks. Glad I did go through the check list of diagnosing as I did find other problems that needed attention listed in my earlier post. Well on to my next check as the car seems to run a little hot half way from 190 and the red line or my temp gauge is just not calibrated right anymore. Well see

[Spider951]

Glad you found the cure; even better that it was not as expensive as the Air Flow Meter. I will keep your experience in mind. Thanks for the info!!