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I need help!
I have a 1986 Alfa Spider Graduate that I have had totally rebuilt. My problem is in the Bosch L-Jetronics system. It bogs down on acceleration at low rpm’s under load until 2,800 rpm, and then it opens up fine with great acceleration. It also has “Hick Ups” (cuts out) during this time. I have replaced all the air hoses in the engine and trunk, injectors, O2 sensor, cleaned out both the oil ventilator canisters, the hidden one too. I have had the fuel ECU, and the Mass Air Flow Meter rebuilt at Fuel Injection Corp, new TPS, tested the AAV, and the VVT solenoid, and they work. New spark plugs cleaned all the grounds, checked fuses. I have two extra ECU’s, one good, and one not so good, and another Mass Air Flow Meter that I bought that said tested and working, but it runs terrible when I put that one on. I am at loss for why it is performing this way. Any suggestions? Thanks!! I have read PapaJam's information religiously too!!
 

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Did you check all the sensors? I know you said you replaced all the hoses but did you check for proper vacuum? Remove oil fill cap or dipstick and listen for an rpm drop. If it doesnt you already have a leak somewhere. Ohm out all the sensors too. These systems are actually very reliable and simple, just need to walk through the steps. It sounds like you have the L-jet troubleshooting link?
 

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Where are the pictures? We like pictures... Then we won't have to ask things like what color your Spider is and other essential information to properly diagnose it.


Have you measured fuel pressure? Checked the Fuel Pressure Regulator (FPR)? A quick & easy check of the FPR is to remove the small vacuum hose and check for the presence of gas. There shouldn't be gas on the vacuum hose side of the FPR. Also check the return line from the FPR to the tank - if it is clogged the FPR can't do its job.
1627148


1627149
 

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check the flywheel sensors, one might be loose in the bellhousing...the connectors too (up by the washer bottle), check those for breakage, for loose or dislodged pins, maybe a frayed or oxidised wire connection.

check and clean the coil connections

check leads, the dizzy cap and rotor arm....look for any odd signs of scraping inside the cap, or arcing, corrosion where leads fit in.
 

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Did you check all the sensors? I know you said you replaced all the hoses but did you check for proper vacuum? Remove oil fill cap or dipstick and listen for an rpm drop. If it doesnt you already have a leak somewhere. Ohm out all the sensors too. These systems are actually very reliable and simple, just need to walk through the steps. It sounds like you have the L-jet troubleshooting link?
I've checked all the sensors, and with the dip stick, I get no change in idle. I replaced all the hoses, engine compartment, and trunk, except the one that runs to below the oil dip stick. Possible my mechanic missed a leak when putting things back together. Thank you!!
 

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check the flywheel sensors, one might be loose in the bellhousing...the connectors too (up by the washer bottle), check those for breakage, for loose or dislodged pins, maybe a frayed or oxidised wire connection.

check and clean the coil connections

check leads, the dizzy cap and rotor arm....look for any odd signs of scraping inside the cap, or arcing, corrosion where leads fit in.
Thanks, I apparently need to disassemble, and reassemble the whole system with a fine tooth comb. Thank you!!
 

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Discussion Starter #9
check the flywheel sensors, one might be loose in the bellhousing...the connectors too (up by the washer bottle), check those for breakage, for loose or dislodged pins, maybe a frayed or oxidised wire connection.

check and clean the coil connections

check leads, the dizzy cap and rotor arm....look for any odd signs of scraping inside the cap, or arcing, corrosion where leads fit in.
Thanks!!
 

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Discussion Starter #10
Did you check all the sensors? I know you said you replaced all the hoses but did you check for proper vacuum? Remove oil fill cap or dipstick and listen for an rpm drop. If it doesnt you already have a leak somewhere. Ohm out all the sensors too. These systems are actually very reliable and simple, just need to walk through the steps. It sounds like you have the L-jet troubleshooting link?
Thanks, I should take it all apart, and reassemble with a fine tooth comb, checking the sensors too!
 

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Discussion Starter #13
Where are the pictures? We like pictures... Then we won't have to ask things like what color your Spider is and other essential information to properly diagnose it.


Have you measured fuel pressure? Checked the Fuel Pressure Regulator (FPR)? A quick & easy check of the FPR is to remove the small vacuum hose and check for the presence of gas. There shouldn't be gas on the vacuum hose side of the FPR. Also check the return line from the FPR to the tank - if it is clogged the FPR can't do its job. View attachment 1627148

View attachment 1627149
The fuel pressure is normal, and I have two fuel pressure regulators, which are good. I need to take it all apart, and put it back together myself. Thank you for the informsation!!
 

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Maybe something useful here: Embarrassing Confession

Especially replies #8 & #14
Thanks! I replaced and checked all the hoses but the bottom one that goes to the bottom of the oil dip stick. Sunday, my mechanic and I are going to take everything back apart, and check it. Since I read the post to open the oil cap, and or dip stick, I did that, and had no idle change.
If in the current state, you can put the dip stick out and there is not the noticeable RPM change then you have an air leak.
Doing that I have an air leak then, thanks!
 

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wouldn't worry too much about a leak in the little oil dipstick hose (by all means get it done, usually just the end 1/2" or so is cracked, snip it off and refit it)
...the car would still drive fine even if you left the dipstick off altogether!

the air leaks you don't want are on the inlet side....spray around with carb spray whilst the car is idling, see if it makes a difference somewhere.
I presume you replaced the 4 intake runners when the injectors were done?
 

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Be careful spraying the carb cleaner near the secondary ignition wires. Unless you like surprise fires! Usually just a quick flash. Trims facial hair. Wear eye protection. Ask me how I know. I have learned that I can spray water (stops the air leak for a moment and changes the RPM) and find the problem in the same way. Still, unless you are certain that the basics are all correct, start there. See my post #12. Good luck, and please post results.
 
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