My sidekick engine only runs on test fuel , NO START.                                  
Assumptions; GOOD motor, GOOD spark and runs on test fuel,  (lost injection? or is it flooding? )

You DID THIS?  (Chads  fuel tank is dry)

or this guy Scotty.  see him do test fuel?

Stotty nails it, note how he jump to the center and works forward or backward from 1,2,3   (bad compression, bad spark, bad fueling) He saves time doing that.



  
THE ENGINE Runs on test fuel
only, also means the engine sounded perfect during the run,  and no engine internal pounding, clanking, or loud rattling, etc.
With the test fuel, the motor started, (may clear a flooded state, too then Re-Flood, ether starting fuel can start a flooded engine and fool you.) and go Verrrroooooommmmmmm,......die slow, and stops. (test fuel ran out... or re-floods.)
There are only 2 class failures here.  ( if flooding? that is a different page.)
  1. Lost fuel pressure  to the injector (30 good,  10 bad,  60 PSI bad.) Sure the filter is new, right? A fuel Squirt test only finds 1 of 6 FPreg fail modes, nor leaking or clogged/leaking injectors.
  2. Electical.  (NOID fails then ECU issues, NOID passes then  bad injector if pressure above is at least 30psi )

IT IS BEST TO DO THIS FIRST:
On the 8v do the injector view test. (dribbling or dead injector)

On the 16v there are many tests,  all  4 leaking, any or all, or clogged, do the balance tests on the injectors.

A technican with a full set of tools, can :  ( a DMM meter, a fuel pressure gauge, and a NOID lamp) can find the reason in 15minutes on a 8v (the 16v is lots more work)
Other Checks and Evidence gathering. (redundant to the 2 links above)
  • 8V TBI engine? look at the injector with your eyes, see 8v link above , is it leaking and the squriting ,while cranking?  Bingo ,you have the solution at hand. Click 8v above and read.
  • Find out if the motor is starving for fuel or is flooding, looking at spark plug tips,  Am I wet or dry, or flooding or starving for fuel.
  • Is the CEL on key on? good, no,then fix that now. If the CEL lamp now glows , insert the Diagnostic jumper and see if the DTC is 12 (good) or some other codes.
  • On any car, the ECU stops injection for only 2 reasons (electric reasons) TPS TP pin at over 3.5v (1v is typical), (stuck in unflood mode is over 3.5vdc ECU halts injections...)
  • Is  the tachometer  dead cranking? can reach up to 300 RPM, If dead, the ECU cuts fuel ) see code 41 below.
  • The ECU is bad if , the Tacho good. the TPS TP pin is at 1v and the injector wires are not cut or shorted and the NOID FAILS.
  • If the NOID lamp passes. and fuel pressure is good, the injector is toast ; if the coil is open in the  injector , it can not be repaired. New injector or if coil good have it cleaned, for $19
  • A clogged up injector.  (it or they can dribble and leak, key on only, the fuel pump test (8 there are) the second tests , is the leak down rate.  Do the full set of tests for leak down on the pump page, and win.
  • An Injector that the coil reads infinity and not 1 ohm is TOAST.
  • A bad ,weak or too powerful fuel pump,  the pressure must be 30 PSI not 1, or 10 or 60 , if the pressure is wrong you have a bad pump, bad FPreg, or the return line is blocked.
  • On all 16v the pump pressure is like 40 keyon, then drops to 30PSI  running, this is very perfect. the 8v just runs the same all time time, key on,or running.  (parked in drive way not climbing Pikes Peak)
  • If 16valves  the injectors take many more tests. (good pressure, no leakage. and no clogs, there are tests for each condition)
  • The 16v, you can look at all spark plugs to see if just 1 is wet, (leaks) or do the pull injector plug test, to find dead injectors running. or do the leak down test, and last the power balance test.  (4 tests here)

I cover Injectors to the max here, check it out.


Test fuel,  fuel dribbled  (sprayed) into induction or sprayed with a can of Instant start in a can into the EVAP nipple or any nipple entering the Plenum. ( CRC now sells this with oil protection ) 3 sprays is good, 30 bad.  dig?
The plenum is that chamber behind or below the throttle body.  
The 8v has a nipple in the front part of the intake behind the thermostat that is easy to get to. and the 16v there or 2 nipples on the top leading edge of the engine (either is ok to use, to inject test fuel)  

Assumptions:
All three fuses for EFI should be good, if test fuel runs motor,   IG-COIL, FI and DOME.  (the dome fuse is ECU memory for DTC storage)
We know spark is good because it runs on test fuel and you checked spark first, right ?  When no spark happens the ECU detects NO spark and CUTS  all fuel all the time !
Battery at 12.6vdc fully changed.  (check at the CIG lighter port KEY ON)  {electrically close to ECU !,dig ?}
Engine Compression is good, test fuel runs motor and it sounds great running on test fuel !
Spark is good, and timed at hear 5degr. BTDC while cranking. (yes, all timing lights work on dead engines, cranking, if not spark is GONE)


No starts only happen for these reasons.
Bad motor ( this page is a good motor, after all it runs on test fuel over and over and sounds, perfect , right?)
Bad spark, you checked that out and it runs on test fuel perfectly.
Bad Fueling, yes that is it, you are here for bad fueling for sure.
The only question is , too rich or too lean.....?
If the 8v don't inject, (look down the TB air horn)  does it inject ? LOOK !  yes, then it is flooding, no ? do the NOID test.
The 16v is more hard, you need to do the 4 tests listed above.




THE 41/42 TEST:   (we do this only if the injector is dead)  Code 41 is Tachometer failure. (not the instrument ,but the input signal to it is dead)
I then leave the DLC Diagnostic . jumper in place.  (skip this for 96 and newer cars)
Turn on the Ignition, do not crank  yet
I see 12 flashing away..... over and over...... (on 96 and newer cars,  the CEL glows steady)
I crank the motor for 10 seconds. (never over 15 sec. as this overheats the starter, and 10sec for me, is max,then let it cool)  ( it takes at least 3 seconds for this test to finish)
usually 3 to 5 seconds is needed, the FSM states, 6 consective fails.  (varies with battery charge and motor compression and age of same)
I release the key, DO NOT KEY OFF , yet., just let the spring in the ignition switch, snap the key back , naturally !
Wait for 1min.
What does the CEL do? Flash 12?, means no problem found, but other codes are bad.
Do you get DTC code 41 or 42? errors  (96 cars or newer look for P0340 or similar error  dead CMP or dead spark errors)

Bingo  problem found !
41 =  ECU thinks sparks is bad, spark can be good, and this can happen, if the suppressor is bad. (tachometer is dead too....) (even a rare shorted out tachmeter can kill injections with code 41)
42=  Dead or intermittent CMP  (the distributor base cam angle sensor)  just 1 fail in 6 good signals triggers,  42.
P0340 = bad CMP (OBD2 code here , 1996 or newer)  same failure as 42, newer car.  RPM dead on OBD2 cars, on the scan tool there is RPM readings... P0355? fails.... these are all hard fails... fix them.

The ECU is programmed to halt injections for  any  code 41 or 42 (P0340).  (this action is for fire/crash  safety and cylinder hydra-locking issues)
41 means the spark readback path through the spark suppressor module is dead, fell off, some ones  failed attempt at a  remote  start system , alarm, or external racing tachometer installation mess up? look for hacking../?
42 means the CMP is dead. ( it is ?) test the CMP.  same for P0340 (96 + cars)  yes?, bad dizzy base.

All the above ass-u-me's  the car is not flooding and shorting out the spark plugs. IS IT?  Flooding is a horse of a different color.

If its flooding use super secret Un-Flood mode, WOT, that is  wide open throttle cranking.

At this point, I'm sure the ECU is happy and that I have spark and ECU likes the spark and that ECU is not locked in un-flood mode and that test fuel tests pass 100%.
The TP pin on the TPS must not be stuck at 3.5v or more, (at idle) or all injectons are cut. (by ECU rules)  This is a key on test,  to check TPS, the motor need  not be running, and is not , on this no start page.
I usually wip out my NOID lamp and check that the ECU is in fact sending Injection pulses, ( I prefer my DSO scope)
If the NOID is dead, I repair the wires to the injector, or replace the ECU. (or bad TPS, or bad tacho signals to ECU)

If the NOID is good, I replace my injectors(s) (after the pump test) , but  you can check the coils for 1 ohm (8v) or near 10 ohms 16v. and all the tests shown here. starting at step 14, and voltage tests !

The 8v motor , the DSO is the only tool to test both sides of the Injector to see what side is dead, the NOID just tells you its Dead. The 8v has both sides of  injector PULSED. Either driver wire dead ,kills all TBI injectors.
The 16v motor has one side of the injector hot all times, key on. 16v  is a Different technology system. The ECU grounds the 16v injectors to fire them. 


So many rumors on injector tests , by those not trying them all under all conditions : Here are some facts !
You can listen to injectors (running) hear them click with a stethoscope (a $4  tool at Harbor Fright (pun)) or other ways. (sonic and mag test tools,etc < see Duanes world.)
You may not be able to hear them while cranking any dead motor, I can not , but I have a special tool to check this, it is a magnetic or sonic pickup tester,  ( this page is a not running engine, so is UNIQUE)
There are sonic testers,  the Waekon (WAE76462)
The mag testers and the far better scope wave forms checks.
With the scope you can even see the injector actually moves its pentile  piston. (back EMF profiling)  I can also use my scope mag probe and see the mag waveform with my scope.
On any running motor, any good stethoscope works, even the $4 harbor fright, tool, so can   screw-driver or a hose held to your ear.  Not one tools proves fuel is flowing, unless you add the balance tests.
but there is a test that does that. and is the pressure balance test, covered in the FSM.
Keep in mind , and injector can clog, past the valve part ! and pass all sonic and mag checks.
Do not be tempted by the dark side, (non techs) by those that do not understand all the ways a system can fail. 
Only flow matters, not just clicking sounds. and there are many ways to stop flow.
I will list them:  (my injector page covers this and is reduntant here)
  1. The 3 places inside that can clog, eg: screens, the pentile or the injection port (tip orifices)
  2. The hidden injector  pintle can jam. open or closed are ANY way it wants. Run Chevron fuel for best play.
  3. The wiring to the injectors are bad. (opens and shorts)
  4. Inputs to ECU wrong, the tacho line dead  and the TPS TP pin over 3.5v.
  5. No fuel pressure (not at 30 PSI min)
  6. Noid tests. No signal to Injector?, don't blame it. (If the NOID fails,  follow this EVIDENCE NOW)  NO NOID NO FLOW !
  7. Click tests. (not clicking ,same deal but I can't hear any injector with my starter pounding away and motor shaking hard.)  ( I lied, my electronic sonic ear stethoscope can hear anything., but no DIY has one, consider that...)
  8. Spark plugs constantly soaked by a stuck upen injector.
The 8v flow can be seen, wow, just look? by taking  off the injection pipe and look down the TB horn.
The 16v takes skill to test and diagnose, its not that hard, there are just 4 tests.

There are 2 balance tests. 16v  (both are shown here, and Duanes fine Video )

1: unplug one injector conn. plug and see the  RPM drop?, if not , it's dead, or bad spark or compression on that cylinder. (but you have HUGE EVEDINCE HERE, follow it,  do the spark and compression tests HERE)
Keep in mind, the engine may  run on test fuel with 1 dead cylinder. 
2: The pump pressure leak down tests.  .
3: The injectors leak test. ( you just get the pressure high, with key on  up to 5 times, then key off, and make sure the pressure dont drop, this finds leaking injector (practice on  a good motor first !) mine holds steady for 5min or more.
4: the CLick test,  using any way you want. Stethocopes work best. or the sonic tester.  ( some use a  rubber hose, or a screwdriver held to injector and ear canal)
 I have and eletronic stethoscope with head muffs. I can hear anything...even cranking,....! most DIY don't have my $40 tool.  so consider that....


The 8v has only 2 tests, the leak down tests, key on, then off.  (see that it holds pressure for 1 min. after key off,? if not the injector leaks. (watch it, leak with eyes, it's not hard to do.) Mine holds for 5min at least.
Then keyon, and get full pressure, then remove the fuel pump relay and then crank down the pressure on the 8v injector line.  This proves injection flow. This works on 8v and 16v TBI or MPI.
Doing the crank down test, is best done on a 16v with one connected at a time.  (see each one and are the equal when done , one at a time)

Wits END?
Send the injector out to be cleaned, if no solution yet?   (do not send out injectors with open coils, that read infinity on the DMM resistance tests )

Last, only  because I don't like eating fuel, is  :  ( I do the NOID test, then pressure tests) The Noid test is safe and fast, the pressure test needs  adapters , a guage and a fuel bath.

Fuel pressure must be checked with a gage, just having some flow works only for CARB;s.  Buy a guage and find out the real truth ( dead, too high, too low, shunt test, leak down test , can't be dont with a finger, sorry !)
The pump is at 5PSI and not 30PSI , bad pump or FPreg. If at 60PSI motor floods and bad FPREG or clogged fuel return line from FPREG to the rear , back to tank.

At this point, the no start reasons, are now known or cured..
Cheers!

Jargon.



rev 5



Privacy Policy