still no start 81 l-jet
01-26-2018, 11:49 PM
#1
still no start 81 l-jet
tested relays, fuel system pressure, injectors getting voltage, tested connector to ecu found bad AFM and replaced with rebuilt. All other tests to ecu ok. Anyone out there with other thoughts or am I looking at bad ecu?
01-27-2018, 03:19 AM
#2
Rennlist Member
Did you find 2 sets of ground wires on the passenger side cam cover, disassemble and clean them?
Can you find an ecu to swap-in?
Or send yours to Richard Andrade for check-out and possible rebuild?
Can you find an ecu to swap-in?
Or send yours to Richard Andrade for check-out and possible rebuild?
01-27-2018, 03:19 PM
#4
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The ground wires are on the cam towers; one on each side. The ground on the top Of the timing cover is for the cold start valve IIRC.
Also clean the ground strap on the PS rear of the block.
Also clean the ground strap on the PS rear of the block.
01-27-2018, 05:07 PM
#5
clean grounds this morning and checked small positive wire at battery. Pulled ecu connector and check all voltage and grounds that lead to ecu all checked out o.k. I'll see if I can find a ecu to swap out. Thanks for ideas.
01-27-2018, 05:25 PM
#6
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Does the engine crank? If not, switch relay XIV with relay X (horn). If that does not work, pull the starter relay and use a fused connector to jumper between pins 87 and 30 (to bypass the neutral safety switch), then try to start. There is an additional ground behind the PS rear quarter panel to clean, that could be the problem. Or the connectors in the spare tire well could be loose.
01-27-2018, 06:06 PM
#7
yes it cranks and fires briefly but injectors not working, if I squirt fuel in AFM engine will keep running have over 2.5 bar fuel pressure and have tried jumping fuel pump and fuel injection relays with same results
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01-27-2018, 08:23 PM
#8
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Pull relay XVI ( L-jetronic) ... 8th slot from right, top row and either jumper equivalent of 30 to 87 ( may be two load sides on that relay, sic 87a/87b - do 'all' 87's) -- or pull relay cover, clean solenoid contact and jam closed with a paper/plastic wedge. See if it now starts.
Less likely is that while fuel pressure may be adequate, flow is not - try relay first.
Less likely is that while fuel pressure may be adequate, flow is not - try relay first.
01-27-2018, 08:52 PM
#9
Rennlist Member
Check passenger side cam cover. I think it is same ground setup as 84. One set of wires is buried ( quite hidden) under the air pump valve located near the o in porsche. The other set of grounds is nearer the c and h. These are ecu and injector harness grounds, very important.
Do you have both sets?
If you feel below the air valve you will feel where the ground attaches. The air valve has to be removed and all the surfaces cleaned to ensure a good ground. Its actually easier to do than it looks.
Regarding the injector relay mentioned by Garth, it can be removed and jumpered in order to test if the relay is the cause of the injectors not firing. That relay is a special one. I like to replace it on these old cars, Roger should have it in stock.
Do you have both sets?
If you feel below the air valve you will feel where the ground attaches. The air valve has to be removed and all the surfaces cleaned to ensure a good ground. Its actually easier to do than it looks.
Regarding the injector relay mentioned by Garth, it can be removed and jumpered in order to test if the relay is the cause of the injectors not firing. That relay is a special one. I like to replace it on these old cars, Roger should have it in stock.
Last edited by Landseer; 01-27-2018 at 11:47 PM.
01-28-2018, 09:45 AM
#10
Thanks for replies I will check ground strap under air pump valve I may have missed that one. I did jumper injector relay but I'll check it out. I'll post back later today. Thanks again!
01-29-2018, 03:11 AM
#11
Rennlist Member
And that relay number is 928.615.119.00. It must be this number relay or your injection system will not work.
And it's the 8th slot from the LEFT, (4th slot from the right) on the top row of relay slots.
And it's the 8th slot from the LEFT, (4th slot from the right) on the top row of relay slots.
Last edited by soontobered84; 01-29-2018 at 03:15 AM. Reason: correction of relay position
01-30-2018, 07:09 PM
#13
Rennlist Member
Anyway, as you have jumpered the ECU relay, and confirmed that the injectors are not chattering away ( use a stethoscope or wood dowel on injector to your ear), then it appears that it is starting on the cold start valve. That can be verified by pulling the '9th' injector harness, which would lead to 'no start'.
As there is no crank shaft position sensor, the early 16V senses engine rotation by means of the distributor after initial start to allow continued operation/main injector firing via the GREEN WIRE - from the distributor to the module on the front right fender ( @ jump post terminal): this is a well known failure, notably due to crumbling plastic terminals.
As there is no crank shaft position sensor, the early 16V senses engine rotation by means of the distributor after initial start to allow continued operation/main injector firing via the GREEN WIRE - from the distributor to the module on the front right fender ( @ jump post terminal): this is a well known failure, notably due to crumbling plastic terminals.
01-30-2018, 11:16 PM
#14
Rennlist Member
$64,000 questions here: #1)Has the car ever run since it has been in your possession?
#2)Has the car been sitting and non-operational for a while?
If the answer to the first question is no and/or the answer to the second question is yes, then I would think that your injectors are gummed up and need to be cleaned.
Not a hard job to do DIY, but easier and a better clean done by professionals.
I await the answers to the questions.
#2)Has the car been sitting and non-operational for a while?
If the answer to the first question is no and/or the answer to the second question is yes, then I would think that your injectors are gummed up and need to be cleaned.
Not a hard job to do DIY, but easier and a better clean done by professionals.
I await the answers to the questions.
02-02-2018, 09:17 AM
#15
the $1500.00 dollar answer is no not running other than present problem and yes probably 2--3yrs sitting outside in texas. Since last post it appears the ecu is not responding to a rpm signal, pin #1 I believe on ecu plug, my question is to test continuity of wiring does ecu pick this up at coil, tack, ignition mod. I think the wire leaving ecu is black/gray or gray/black not sure haven,t looked at connector yet. Any thoughts here? Fuel system has been cleaned, fuel tank removed all filters,screens replaced injectors, regulators , damper, rails cleaned new fuel lines all before trying to start. Been thru this with my 1979 cis version that runs, Thanks for responses in advanved
