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> Help Need D-jet Jedi!, No full load enrichment
j3vw
post Aug 18 2010, 09:28 AM
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Hey Folks...little help?.......73 1.7...idles pefect, ignition system and valves good.....idle air fuel mix fine...over aprox 2500 rpm....leans out bad...tested press sensor, vac.. good resistance good...all indicators are full load enrichment not happening...any ideas?...I do alot of L-jet work and ECU"s are rarely the problem..

Thanks!
Rich
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realred914
post Aug 18 2010, 09:37 AM
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QUOTE(j3vw @ Aug 18 2010, 08:28 AM) *

Hey Folks...little help?.......73 1.7...idles pefect, ignition system and valves good.....idle air fuel mix fine...over aprox 2500 rpm....leans out bad...tested press sensor, vac.. good resistance good...all indicators are full load enrichment not happening...any ideas?...I do alot of L-jet work and ECU"s are rarely the problem..

Thanks!
Rich



test a few mor things, make sure head temp sendor is ok resistance. make sure you have no manifold vacuum leaks that can mess up the pressure sendor reading. make sure fuel pressure is ok, and no restrictions in fuel filter.

good luck
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j3vw
post Aug 18 2010, 09:44 AM
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QUOTE(realred914 @ Aug 18 2010, 07:37 AM) *

QUOTE(j3vw @ Aug 18 2010, 08:28 AM) *

Hey Folks...little help?.......73 1.7...idles pefect, ignition system and valves good.....idle air fuel mix fine...over aprox 2500 rpm....leans out bad...tested press sensor, vac.. good resistance good...all indicators are full load enrichment not happening...any ideas?...I do alot of L-jet work and ECU"s are rarely the problem..

Thanks!
Rich



test a few mor things, make sure head temp sendor is ok resistance. make sure you have no manifold vacuum leaks that can mess up the pressure sendor reading. make sure fuel pressure is ok, and no restrictions in fuel filter.

good luck

Fuel press is spot on both high low rpm
...no major leaks...i'll test cyl head temp ...I've seen them cause excess rich running but not lean?
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Bleyseng
post Aug 18 2010, 10:00 AM
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check out the TPS and also how do you know its leaning out? Do you have a AFR tester on the tailpipe with a O2 sensor? ie a LM1?
Lots of time the poping and spitting is caused by the dizzy not advancing due to old grease freezing the weights inside.
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j3vw
post Aug 18 2010, 10:07 AM
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QUOTE(Bleyseng @ Aug 18 2010, 08:00 AM) *

check out the TPS and also how do you know its leaning out? Do you have a AFR tester on the tailpipe with a O2 sensor? ie a LM1?
Lots of time the poping and spitting is caused by the dizzy not advancing due to old grease freezing the weights inside.

Yes ..using LMI....AFR a bit lean at idle 15.1...will adjust later...over 2k rpm...shoots to high 20's afr( while driving)....no ignition breakdown at idle or low rmp..idles great and pretty smooth just sitting at higher rmp...
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Bleyseng
post Aug 18 2010, 10:15 AM
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What is the number on the MPS?
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j3vw
post Aug 18 2010, 10:27 AM
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QUOTE(Bleyseng @ Aug 18 2010, 08:15 AM) *

What is the number on the MPS?



-100 049

cyl head temp within scecs
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Bleyseng
post Aug 18 2010, 10:46 AM
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Untampered with? meaning factory unit with the epoxy seal over the WOT stop?

If all these Djet parts are stock in good condition then I'd look for a vacuum leak as the AFR should be 13.5-14 to one at 2500rpms...

Check the injector seals, manifold gaskets, throttle body seal etc as air is bleeding in to mess with your AFR..

Last thing I would do is adjust the MPS but IF everything else checks out to spec then look at that.

If its a rebuilt unit, go ahead and adjust it. I can write how if you need it.
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Bleyseng
post Aug 18 2010, 10:47 AM
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Untampered with? meaning factory unit with the epoxy seal over the WOT stop?

If all these Djet parts are stock in good condition then I'd look for a vacuum leak as the AFR should be 13.5-14 to one at 2500rpms...

Check the injector seals, manifold gaskets, throttle body seal etc as air is bleeding in to mess with your AFR..

Last thing I would do is adjust the MPS but IF everything else checks out to spec then look at that.

If its a rebuilt unit, go ahead and adjust it. I can write how if you need it.
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j3vw
post Aug 18 2010, 10:59 AM
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QUOTE(Bleyseng @ Aug 18 2010, 08:47 AM) *

Untampered with? meaning factory unit with the epoxy seal over the WOT stop?

If all these Djet parts are stock in good condition then I'd look for a vacuum leak as the AFR should be 13.5-14 to one at 2500rpms...

Check the injector seals, manifold gaskets, throttle body seal etc as air is bleeding in to mess with your AFR..

Last thing I would do is adjust the MPS but IF everything else checks out to spec then look at that.

If its a rebuilt unit, go ahead and adjust it. I can write how if you need it.

All OG...looks untampered...no Vac leaks I can detect..(starter fluid)...the set screw on bottom of ECU is dinged so I believe thats why the idle AFR is off a tick.
Is the large set screw on base of MPS for full load enrichment?
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Bleyseng
post Aug 18 2010, 12:22 PM
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and the ECU is a 037?
fuel pressure stays at 30psi when you rev the engine?

The WOT stop (big slotted plug) must come out and to do that you remove all the epoxy with a heat guy and dental picks.
I am still thinking something is wrong as "IF" you have all the correct FI parts and they are working then its a fuel or spark issue. The Djet stuff is hardwired so if they are the right years and engine setup it works, no magic to it.
If you change the engine size or other things, yeah its gonna be off.

Check your fuel pressure to see what it is running. See what happens when you turn it up to 36lbs....
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underthetire
post Aug 18 2010, 12:26 PM
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I might add to remove the connector for the air intake temp sensor as well and see how it runs.
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j3vw
post Aug 18 2010, 01:08 PM
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QUOTE(underthetire @ Aug 18 2010, 10:26 AM) *

I might add to remove the connector for the air intake temp sensor as well and see how it runs.

Constand 29lb on fuel pressure....no variation or bobble...clean even spray pattern on injectors....
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j3vw
post Aug 18 2010, 01:13 PM
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QUOTE(Bleyseng @ Aug 18 2010, 10:22 AM) *

and the ECU is a 037?
fuel pressure stays at 30psi when you rev the engine?

The WOT stop (big slotted plug) must come out and to do that you remove all the epoxy with a heat guy and dental picks.
I am still thinking something is wrong as "IF" you have all the correct FI parts and they are working then its a fuel or spark issue. The Djet stuff is hardwired so if they are the right years and engine setup it works, no magic to it.
If you change the engine size or other things, yeah its gonna be off.

Check your fuel pressure to see what it is running. See what happens when you turn it up to 36lbs....

all apears OG and stock ...this car has not been McGuyvered..still had OG palstic fuel lines...Nice.....if fuel were correct and spark was weak, it would run rich under load as Djet does not adjust conditionally..only, start, mid and full load..correct?...wich way is proper adjust once access to screw??

Thanks!
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realred914
post Aug 18 2010, 01:22 PM
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QUOTE(j3vw @ Aug 18 2010, 12:13 PM) *

QUOTE(Bleyseng @ Aug 18 2010, 10:22 AM) *

and the ECU is a 037?
fuel pressure stays at 30psi when you rev the engine?

The WOT stop (big slotted plug) must come out and to do that you remove all the epoxy with a heat guy and dental picks.
I am still thinking something is wrong as "IF" you have all the correct FI parts and they are working then its a fuel or spark issue. The Djet stuff is hardwired so if they are the right years and engine setup it works, no magic to it.
If you change the engine size or other things, yeah its gonna be off.

Check your fuel pressure to see what it is running. See what happens when you turn it up to 36lbs....

all apears OG and stock ...this car has not been McGuyvered..still had OG palstic fuel lines...Nice.....if fuel were correct and spark was weak, it would run rich under load as Djet does not adjust conditionally..only, start, mid and full load..correct?...wich way is proper adjust once access to screw??

Thanks!


the ecu screw is for idle trimming, clockwise richer, is the direction of turning.

good luck
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Bleyseng
post Aug 18 2010, 05:31 PM
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ok, have you put a vacuum gauge on it to see what it reads at idle? Should be a steady 15hg or better.
Have you checked the spray pattern of the injectors? Nice clean fan not a drizzle....
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j3vw
post Aug 18 2010, 05:36 PM
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QUOTE(Bleyseng @ Aug 18 2010, 03:31 PM) *

ok, have you put a vacuum gauge on it to see what it reads at idle? Should be a steady 15hg or better.
Have you checked the spray pattern of the injectors? Nice clean fan not a drizzle....

yep 15 hg at idle...good coompresion, leakdown test ect...block is stout,,,very good pattern all around....I noticed the housing for the ECU ...I can send it FI Corp to be tested as a last resort
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Bleyseng
post Aug 18 2010, 05:40 PM
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Hell, borrow a known good 037 ECU from somebody..
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j3vw
post Aug 18 2010, 06:03 PM
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QUOTE(Bleyseng @ Aug 18 2010, 03:40 PM) *

Hell, borrow a known good 037 ECU from somebody..

just noticed I did not finish my thought...bottom of ECU housing is pretty rusty....Is it common for D-jet ECU's to develop a glitch or do they just usually crash?
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Bleyseng
post Aug 18 2010, 06:45 PM
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its not a computer really its just a bunch of resistors and pots for injector durations etc...I'd try another one now.
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