QuestionQUESTION: Hi, a few days ago, my fuel pump stopped working, so I replaced it with a new one.
Now, when I crank the engine it don't want to start. I have spark in the cables, and the pump is pumping the first 2 second on contact, and permanently during crank.
I have checked for fuel pressure and it is present. If I get the injector manually excited I can hear it pulverazing fuel, and if inmediately after that I crank, the engine starts and runs for a few seconds then turns off no matter the accelerator position. I guess the injector is not working once the engine starts or is not receiving signal from the computer.
What can I check to test this?
Thanks.
ANSWER: Hi German,
Have a helper crank over the engine while you observe the spray pattern of the fuel as it hits the throttle body plate directly underneath it. It should have a fine symmetrical pattern and continue for as long as it is cranking and running. If it is drippy after shut off or uneven then I would suspect the injector is failing.
Two other ideas:
Do a fault code readout using the ignition key:"on-off-on-off-on and leave on" doing that in 5 seconds or less elapsed time. Then watch the check engine light, which remains 'on', to see it begin to flash, pause, flash, etc. count the number of flashes before each pause. Then repeat the process to be assured of an accurate set of flash counts. Then tell me the counts in the order of appearance and we'll go from there to figure out what the code numbers are telling us that the engine computer observes to be wrong.
Check the egr valve to make sure that it isn't stuck slightly ajar which would thin out the mixture such that you won't get an idle condition. The valve is located on the firewall side of the engine, close to the front of the engine and is mounted vertically. It has a round vacuum operated top, a valve body that is bolted to the intake manifold, and between those two parts is a flange inside of which is the stem of the valve. The stem has a slot into which you can insert the tip of a screwdriver to be able to move the stem up and down, against spring-action in one direction that drives it down so as to close the valve. Move the stem and make sure it moves freely and that the spring action closes it. It is sticky and doesn't close tightly via the spring-action then spray some WD-40 on the stem where it enters the valve body and work the stem to free-up the 'action'. Then see if the engine will start and run.
Roland
PS Please 'rate' my answer and consider giving a 'yes' answer to the question about a nomination of me to be volnteer of the month. Thanks
---------- FOLLOW-UP ----------
QUESTION: Thanks Roland. The code readout shows the usual 12 & 55, and also a 27 (which I saw in the Haynes manual is related to the injector). I'm going to check the way the injector is spraying the fuel.
The egr valve appears to be working fine, it moves fine up and returns down by itself smoothly (I sprayed some wd40 just in case).
Now i have a cable directly from the ASD green/orange cable attached to the injector positive and a test lamp connected too. When I switch to contact the lamp glows at the same time with the pump for those 2 seconds of pressurization. And then, when I crank it stills on during the cranking. So the injector have a positive line and should be working I guess.
By the way, the last tries I saw a backfire trough the throttle body.
ANSWER: Hi German,
I agree that the 27 code says that there is something amiss with the injector circuit. Make sure that the wire to the injector doesn't have melted insulation and could be shorted perhaps. Otherwise if there is dripping/after drip/asymmetry then you will want to replace the injector as shown in the Haynes. It could be dumping so much fuel that it would cause a backfire. It costs about $150 at a dealer, maybe less at a parts store. But they do wear out. I had to replace the one in my '89 2.5L.
Roland
---------- FOLLOW-UP ----------
QUESTION: I was doing more testing this morning, and I can't find any wiring diagrams showing the lines that manage the injector. I know that the positive is provided by the ASD relay (dark green/black cable), but I can't find the negative cable. I'm suspecting the signal is no going tru the cable, so i'm trying to get this cable the closest to the SBEC to see if the computer is emitting the signal to the injector.
On the injector connector, I have a dark green/orange and a white(?)/black.
Any ideas?
AnswerHi German,
The white/dark blue wire goes to pin 16 or the sbcc and the injector is activated when that wire is momentarily grounded. I don't think you will see the pulse with an ohmmeter as it is too fast. Have you checked the resistance across the injector pins? It should be a little less than 1 ohm. Also, is there a spray pattern? If not then either the injector is not working or the wire is not being pulsed to ground by the sbcc. If you have spark you should have the pulse to ground. But if you don't have spark then I would suspect that you have a weak/defective hall effect sensor in the distributor. But if that were the case you would have a code 11, which you said was not there. So those are the possibilities as I see it.
Roland
