calling all TPI guys-Flooding

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SSClassic

Greasemonkey
Aug 12, 2017
109
114
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Pennsylvania
so some have seen my build thread & some have not,ive got an 88 monte ss with a 305 thats been converted to an 88-89 TPI.i have an 88 harness & ECM (1227165) MAF used with an 89 intake/runners/plenum with a custom PROM (CS deleted)from Sinister Tech. Problem is injectors are flooding the cylinders to the point of hydrolock on prime cycle
,ive been through 2 oil/fuel changes,replaced a fuel rail,rebuit a fuel rail,2 sets of injectors,2 sets of plugs & checked the AFR twice. i have 46lbs of FP on prime but it dosent hold,does hold when cranking.ive done alot of testing on injectors all seem to check out 12v
With the ECM disconnected:
Injector ground wires do not have continuity to chassis ground.
All right side injectors grounds are connected to each other.
All left side injectors grounds are connected to each other.
Right and Left injector wires are not connected to each other.

With ECM connected:
All injector ground wires have continuity to chassis ground - (1.52 kOhm)
Right and Left injector wires are all connected to each other via ecm

after weeks of checking everything & testing,i believe the PROM may be the problem trying to compensate fuel on startup due to cold start being deleted.ive removed all plugs & rolled engine over to push out the fuel,unplugged the injector pigtails & tried to start.it started for 3-5 sec.put pigtails back on & plugs soaked.
any ideas or suggestions cause all i got left is the prom to blame.thanks guys
 

Injectedcutty

G body LS mafia
Nov 24, 2014
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22,807
113
Louisville, KY
Ha!!!!! Exact same problem I fought with on my old TPI setup. I had plenty of fuel pressure on prime cycle, but went to zero afterwards and wouldn't fire and would flood.

My solution: I added a one way check valve on the feed line. I have AN braided line so adding in the valve was easy with some fittings. There are adapter fittings to go from AN to flare or NPT whichever you need.
The check valve allows the fuel to flow forward during prime cycle, but stops it from flowing back to the tank keeping pressure on the rails.
No joke, I fought this problem for years, and a $40 check valve fixed it and I didn't have an issue after install.

Hope this helps,
Scott
 
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SSClassic

Greasemonkey
Aug 12, 2017
109
114
43
Pennsylvania
Dorman Products 800-196
Fuel Line Fuel Check Valve Kit 3/8" Hose Barb to 3/8" Hose Barb Tubing
326-800-196.jpg


Part Number: 326-800-196
 
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Injectedcutty

G body LS mafia
Nov 24, 2014
6,057
22,807
113
Louisville, KY
Dorman Products 800-196
Fuel Line Fuel Check Valve Kit 3/8" Hose Barb to 3/8" Hose Barb Tubing
326-800-196.jpg


Part Number: 326-800-196
That might do the trick. You just need to make sure you get fuel injection specific hose clamps to withstand the pressure to prevent leaks.
 
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Injectedcutty

G body LS mafia
Nov 24, 2014
6,057
22,807
113
Louisville, KY
This is what I used, like I mentioned adapter fittings are available. The Dorman unit is likely more cost effective though.
Screenshot_20180509-073844.png
 
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SSClassic

Greasemonkey
Aug 12, 2017
109
114
43
Pennsylvania
im going to see what the part stores have in my area and go from there,sure do hope this does the trick.thanks for the quick reply scott
 
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Wraith

Royal Smart Person
Jan 13, 2013
1,599
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DFW, TX
With the ECM disconnected:
Injector ground wires do not have continuity to chassis ground.
All right side injectors grounds are connected to each other.
All left side injectors grounds are connected to each other.
Right and Left injector wires are not connected to each other.

With ECM connected:
All injector ground wires have continuity to chassis ground - (1.52 kOhm)
Right and Left injector wires are all connected to each other via ecm

after weeks of checking everything & testing,i believe the PROM may be the problem trying to compensate fuel on startup due to cold start being deleted.ive removed all plugs & rolled engine over to push out the fuel,unplugged the injector pigtails & tried to start.it started for 3-5 sec.put pigtails back on & plugs soaked.
any ideas or suggestions cause all i got left is the prom to blame.thanks guys

Are they reading ground with power on to the ECM or when not powered?
 

SSClassic

Greasemonkey
Aug 12, 2017
109
114
43
Pennsylvania
lol auto zone guys are such a joke,ill have one from napa in the morning.ill defiantly post my results
 
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SSClassic

Greasemonkey
Aug 12, 2017
109
114
43
Pennsylvania
Are they reading ground with power on to the ECM or when not powered?
both to determine if the injectors are being grounded outside the ecm,or within like their supposed to.
 
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