1987 tbi 350 cranks wont run

[Irish_Alley]

If the injector turns out good then to test the pick-up coil, first disconnect the white and green module leads. Set the ohmmeter on the high scale and connect it between a ground and either the white or green lead. Any resistance measurement less than infinity requires replacement of the pick-up coil. I'm kind of doubtful of it being bad but just one less thing that it could be. By time you take the distributor apart you can swap it out with another

[beavo]

ok guys finally got time to work on my truck i changed the dist for one that i know is good and ran the test with my light hooked to the b+ and i have no pulse coming through that wire so once again back to square one thanks again

[VileZambonie]

Circuit Description :

This chart assumes that battery condition and engine cranking speed are OK, and there is adequate fuel in the tank. This chart should be used on engines using the Model 220 throttle body.



 Test Description : Numbers below refer to circled numbers on the diagnostic chart.

A "Service Engine Soon" light "ON" is a basic test to determine if there is a 12 volt supply and ignition 12 volts to ECM. No ALDL may be due to an ECM problem and CHART A-2 will diagnose the ECM. If TPS is over 2.5 volts the engine may be in the clear flood mode which will cause starting problems. If coolant sensor is below -30~C, the ECM will provide fuel for this extremely cold temperature which will severely flood the engine.
Voltage at the spark plug is checked using Spark Tester tool ST 125 (J26792) or equivalent. No spark indicates a basic ignition problem.
While cranking engine there should be no fuel spray with injectors disconnected. Replace an injector if it sprays fuel or drips like a leaking water faucet.
Use an injector test light like BT8320, or equivalent, to test each injector circuit. A blinking light indicates the ECM is controlling the injectors.
This test will determine if there is fuel pressure at the injectors and that the injectors are operating.
 Diagnostic Aids :

If no trouble is found in the fuel pump circuit or ignition system and the cause of a "Engine Cranks But Will Not Run" has not been found, check for:



Fouled spark plugs
EGR valve stuck open
Low fuel pressure. See CHART A-6.
Water or foreign material in the fuel system.
A grounded CKT 423 (EST) may cause a "No Start" or a "Start then Stall" condition.
Basic engine problem.CHART A-4 - INJECTOR CIRCUIT DIAGNOSIS




 Circuit Description :

This chart should only be used if diagnosis in CHART A-3 indicated an injector circuit problem. If both injector circuits fail to blink when tested, diagnose, one injector circuit at a time.



 Test Description : Step numbers refer to step numbers on diagnostic chart.

This step tests for 12 volts to the injector. It will also determine if there is a short to voltage on the ECM side of the circuit.
This test checks for continuity to the ECM.
 
 

[beavo]

i done the test that the chart instructed i hooked to a ground and probed my ecm plug in 16 and 14 they both lit up so i hooked to B+ and ran the test on the other side of the plug 16 lit bright and 14 was very dim is this a symptom also the chart says the ecm or the connections are faulty but i had already tried my ecm on my dads van and it run and the connections in both the ecm and the plug look good so im still at a loss thanks again yall
 

[VileZambonie]

So test light to ground key on engine off both injectors have B+? Test light to B+ other terminal no blink when cranking? If this is correct then you have lost the injector driver. Go directly to the cavity on the ECM Either D14 or D16 and backprobe it there. If you have the driver there then you have an open circuit.

[beavo]

so i checked the d14 d16 in the ecm plug with my light and it lit well on both of them so i hooked my light to the hot on the batt. and checked the other side of the plug as i assumed that the other side was a ground and one lit well and the other was real dim does this mean anything thanks again

[VileZambonie]

D14 or D16 is being backprobed. Do not unplug the connector. Use a paper clip to make contact with the terminal (don't jam it in there) Hook your test light to B+ and the paper clip -then crank the engine. Do not hook the test light to ground this won't validate what you're looking for. It should cause your test light to blink while cranking. Depending on your test light it may be a dim blink so look carefully.

[beavo]

sorry it has takin me so long to get back on here but i checked the ecm like you said i cant see a blink it only slightly dims when you crank but no flash so please tell me what to do know cause im completely lost thanks again

[VileZambonie]

OK start over since it's been a while. Test light to B+ touch ground, test light illuminates. (yes) take test light and backprobe cavity D14 or D16 with a paperclip and test light should blink while cranking the engine. Report

[beavo]

Yes correct this is what i done no blink. Light does dim slightly of course when cranking but no flash. Thanks Again.

[VileZambonie]

And you have good spark?

[beavo]

if you mean spark on the plugs i havent visually checked it since when you prime it with gas it runs so i thought it was ok
thanks again