L Jet fine, the very not fine

[DPeterson3]

Just brought an 86 Spider out of 9 year hibernation. Wouldn't run, so required new injectors, two fuel pumps, filter, fresh fuel, and a variety of clean ups. Bang. Started right up and ran great. Drove around town for about 15 minutes. On the way home it stuttered once. Didn't think anything about it. Took it out a bit later and within a mile it started to run rough and lose power. Wouldn't respond to throttle. Finally quit. However, note the following...

Important note: If I cut off the ignition, wait even 3 or 5 seconds while coasting down the road, and start it up, I get about 3 to 10 seconds of good power and response, then it starts losing power, idles rough, then dies. Off with switch and restart, and it has good full power for a few seconds.

I'm going to try it in the morning to see how it behaves when totally cold.

When I did the off and restart going up a hill toward home, it actually ran better going up the hill, but once level it reverted to losing power. On some occasions it will lose power, then suddenly things start working again, but only for a few seconds. The off/on trick works every time, however.

Seems related to the thread at Puzzling fuel system symptoms '86 spider

but that thread never really came back with a solution. It was quite cool here today in northern Nevada, so no vapor lock.

Fuel injection experts out there?

Don

[papajam]

Welcome to the Board, Don!

Sounds to me like a fuel issue but the only way to help diagnose this ( without blindly throwing parts at the car) would be to observe the fuel pressure under driving conditions. Do you have access to a pressure gauge?
It wouldn't to check the air intake hose from the Air Flow Meter (AFM) to the intake plenum for cracks.

[Zunige]

Welcome to the BB!

Like papajam said (and he's a real guru) it sounds like a fuel delivery issue. I'm wondering if you cleaned the fuel tank... I say this because going uphill could help keep tank sludge from clogging up the fuel line, and once the car levels off it would start acting up. Techron is an excellent product (the only one in my opinion) that will really clean the system, but it sounds like you should really inspect your tank first. If the tank is clean, I wouldn't hesitate to use the Techron.

Best regards,

[DPeterson3]

Tank was not cleaned, but it was thoroughly drained and completely refilled with fresh premiu m. New in-tank pump and sock-filter, new in-line pump and filter. New AFM to plenum intake hose. Old one looked fine, but had slightly shrunk, so I put on a new one.

The uphill improvement may have been a coincidence. As I noted, the power bursts are a bit erratic, except for the first few moments after key off/key on. I doubt crud in the tank would go from the tank to the engine is less than 1 second, which is about the time from beginning up the hill to the brief improvement in power.

I'm going to re-check all possible air leaks today. As I noted, it ran great for about the first 15 minutes after the clean up and repair. I'm wondering if the key off/key on doesn't get me a little burst out of the cold start valve correcting aa lean mixture due to airleak in intake tract somewhere.

I'll be monitoring this thread and appreciate everyone's help. I was rather pleased that it started and ran so well after 9 years of sitting. Sigh.

Only apparent other issue is interrmittent fuel level indication.

Thx.

Don

[papajam]

Quote:

Originally Posted by DPeterson3 Only apparent other issue is interrmittent fuel level indication.

[DPeterson3]

Thanks Papajam,

When putting in the new in-tank pump, I did some testing and it seems that the fuel tank itself is not grounded. I didn't spend much time thinking about this, but there is a separate ground wire to the sender, which is well connected and provides a good continuity test. Before putting in the in-tank pump (had to wait on it to arrive), I got the car sort of started without it. The fuel tank was full of fresh fuel, so figured it would pick up OK. If the in-tank pump is intermittent, would it cause a fuel-feed problem with a full tank in level attitude at partial power or idle? Once the rough running starts the idle goes to hell also, and before this problem started the idle was dead smooth.

BTW, one of my new pumps is noisy as blazes. Not sure which. The in-line pump is not Bosch, but is aftermarket. I may buy a Bosch just on general principals.

Thx,
Don

[DPeterson3]

Checked all hoses. Couple needed a bit of tightening, and the 4 intake runner clamps were completely loose from my re-installation.

However, symptoms exactly same. Runs great while cold, then progressively worse from about 5 - 7 minutes after start up, until it gets very hard to keep it running. I have to believe it is a lean-cut. Heard a couple of coughs from intake side upon giving it throttle (unresponsive). My guess is that the cold-start valve makes it just rich enough to run, but once that goes offline I don't have sufficient fuel feed.

I plan to order a new Bosch in-line pump, mainly because this blue POS is really noisy. Not confidence inspiring. All my tools are stuck in another state being moved, so will try to find a good local shop with L-Jet experience to do fuel pressure test, etc.

Thanks,

Don

[ghnl]

I read somehwere here that Centerline stopped selling the replacement fuel pumps because of poor quality. IIRC, they'd work for a short while but they (Centerline) were getting a lot of returns for early failure/defective pumps.

I also recall a fellow BB member who was ready to toss a match into the fuel tank. His car would start, seem to run OK but then cut out when he tried to accelerate. Coast to the side of the road, wait a few minutes and it'd re-start. He had already replaced fuel pumps, filters, and fuel lines so he was sure it couldn't be any of those. It was. It was a defective fuel hose. It had an internal fault that acted like a one-way valve. Under low flow situations fuel would pass by. But when he opened the throttle the flap of rubber would block the fuel line. After sitting for a few minutes the pressure in the hose would decrease, the flap would open and it'd run.

Here's a link to the L-jetronic diagnosis page. Note that I need to edit the info about the CSI (Cold Start Injector) The correct info is here: Cold Start Injector Logic (look for PapaJam's reply).

Also note that the most common trouble areas in our Spiders are intake air leaks and ground connections. It is always worth checking (and double checking...) those items.

[Tifosi]

For some reason I keep wanting to think 'loss of fuel pressure/volume'.

By happenstance has the regulator been checked anywhere though all of this process? (I didn't see where if it was)

[DPeterson3]

Latest on not-so-fine L-jet.

New Bosch in-line pump and new Bosch pressure regulator. Replaced several vacuum lines. Same symptoms, only they are starting sooner. That may be because the outside temps were in the hi 60's and 70's today, where the earlier notes came from running it when the outside temps were low 50's.

I'm still thinking it is a lean cut, due to cold-start cutting off and insufficient fuel after that. I'm about out of parts I can change, though. Didn't mind the fresh parts due to 9 years in barn, but I'm about out of ideas.

MAS? Throttle position switch?

Thanks,

Don

[dpoole]

so what was the fix?

[DPeterson3]

Sorry for the slow reply, but the AlfaBB people seem to have given up getting email notices sent to me.

Anyway...

In the end, the fix involved two new pumps, master relay, thermo-time switch, and new injectors. Plus, all the stuff you would also do, such as filters, hoses, and cleaning. I also changed - but probably did not need to change - the pressure regulator, and cold start valve.

The whole problem was made worse by taking the car to a couple of dope-head idiots who said they were experts in L-Jet work. They had no clue, nor much motivation to get up from the TV.

I also fixed the charging problem by replacing the wire between the alternator and the main junction box.

Also, recently a new water pump, which seems unsurprising given the 9 year sit in a garage. Also new leather seat covers, Koni's, one caster rod bushing, one tie-rod end. The AC compressor was more or less just resting on the oil sump, so I just removed it. The system still had pressure, so I may put it back some day. New motor mounts made all the rattling noises go away. Yippee.

Now it's my daily driver. It still has odd squeaks from sitting for so long, but all in all it's OK. The water temp can get up a bit during the climb up to Lake Tahoe on a 98 degree day, but I'm playing like that's normal.

The only nagging problem is an occasional "chuff!" should from the engine bay. I'm guessing I have a very intermittent intake valve leak, but I don't get any pause in power when it happens. Just a sharp "chiff" sort of sound, and not like I'm use to hearing with an exhaust valve leak.

Mostly, all is good.

Don

PS - now I'm taking apart my 102 2000 Roadster. This is the depressing phase, when each new thing comes off and I see just how much work there lies ahead.