bigodub93

i wanted to know what tells the ecu to ground injectors. is it a sensor? where does it come from. i am not getting injector pulse and i need to know what is causing this.

mmuller

what tells the injectors to fire is the ecu

blkb18

Any codes? Do you have a good signal from the cam/crank sensor?

bigodub93

all 3 ecus i have tried dont fire the injectors. they are ran stright to the injectors to the ecu. what should the voltage be to the cam and crank sensors. 5 or 12???

Chiovnidca

Does it have spark?

GhostAccord

Your ECU contains memories (look-up tables/maps) for the basic pulse widths at various engine speeds and manifold pressures/ RPM vs MAP. The basic pulse width or duration, after being read out from the map, is further modified by signals sent from various sensors to get the final pulse width. TDC/CKP/CYP, MAP, ECT, IAT, TPS, O2 x2, VSS, and the BARO sensors just to name a few.

Make/model/year of car and any possible engine swap info would help us to help you figure this out.
How do you know that you are not getting any injector pulse?
Is your fuel pump working?
Have you checked your Main Relay?
What type of injectors are you using, Low or High Impedance?
Are you still using stock injectors or did you pick up new ones?

bigodub93

i have spark. i know i dont have pulse because i used a noid lite kit and it does not light at all. main realy was checked and it is good. shoot carb cleaner in there and it fired right up, than shut off. fuel pump primes and i have fuel pressure. when i turn key to on i get voltage to injectors.
89 std hatch,d16z6 motor,z6 dizzy,z6 manifold.
also im pretty sure when i bought the car it have obd1 injectors running in it with a resistor box, but the car was obd0. now i have switched it to obd1 whith the harness and the z6 dizzy and 4-wire o2. i will postfist pic old old injectors and new ls injectors they look exactly the same.
http://img88.imageshack.us/img...0.jpg
then the new ones
http://img88.imageshack.us/img...9.jpg

Chiovnidca

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by bigodub93 &raquo;</TD></TR><TR><TD CLASS="quote">i have spark.</TD></TR></TABLE>
Good, that rules out a lot of possibilities. Now does it have 12 volts at the injectors?

bigodub93

it was 12 before i put the resistor box back on my car, now i cant remember what it read after that.

GhostAccord

If you are using the resistor box now that could be the problem. If you are using OBD1 92-95 LS 240cc injectors they are high impedance (saturated). They do not use the resistor box. The OBD0 90-91 LS injectors are the 240cc low impedance (Peak & Hold) injectors that require a resistor box.

bigodub93

can you tell me what injectors these are. they both look exactly the same and one for sure is obd1 ls injectors(2nd pic) the other came in the car but was running with the resistor box. but like i said they look exactly the same. and the injector plugs are grey.

mmuller

do you have a multimeter?
if so measure the ohms to see what injectors they are , if you get 2.5/3, then they are peak and hold

GhostAccord

^^ Measure the ohms between the two male pins on the injectors. Make sure you check them all because by the sounds of it you may have a set of each.

2.5 - 3 Ohms = Low Impedance require a resistor box.
8 - 10 Ohms = High Impedance and they do not require the resistor box.

bigodub93

they all ohm out at 12

GhostAccord

If they are all 12 Ohm then they are high impedance, you don't need the resistor box. Just wire them strait to there respective ECU pins.

Chiovnidca

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by GhostAccord &raquo;</TD></TR><TR><TD CLASS="quote">If they are all 12 Ohm then they are high impedance, you don't need the resistor box. Just wire them strait to there respective ECU pins.</TD></TR></TABLE>
The ground side of both types of injectors should go direct to the ecu pins. The resister box should be in the power side. And yes, he should remove it.

bigodub93

ok so i rewired them but still no start. ground stright to ecu and yellow/blacks to the 2 yellow/black wires comming out of my round harness.

GhostAccord

When you go to start your car does the Check Engine light come on for 2-3 Seconds? Have you checked the ECU for any stored codes.

If you know that the ECU that your using is good and that you have fuel pressure at the injectors these three sensors are what to look at next.
Check for any of these stored codes
4 - Crank Position sensor (CKP)
8 - Top Dead Centre Position Sensor (TDC)
9 - Cylinder Position Sensor (CYP)

If you do not have a stored cel code check to make sure that all the wires for the 3 sensors above are tight and that they are clean and have good contact.

CEL 15 - Ignition Output sensor is the last place to check.

Chiovnidca

He already said it has spark. Unless that's changed.

GhostAccord

Yes I see that, so what do you think the problem is then?

Lets break it down to trouble shooting A,B,C's & 1, 2, 3's

1. ECU - Tried 3 ECU's, with voltage at the injectors. No go!

Q to OP - Are the injectors wired properly? Double and triple check all of your wiring and connections both (+) & (-)

2. Other Fuel Supply
- a) Fuel Pump - OP says he has fuel pressure
- b) Main Relay - Fuel pump charges with ign II
- c) Fuel Filter - Fuel pressure

Q to OP - Is there fuel pressure at the fuel rail? Place a rag/shop towel over the banjo bolt on the fuel rail and slowly loosen to check for fuel pressure.

3. TDC/CKP/CYP sensors - Has spark

4. Ignition Output Signal - Has spark

Check again to make sure that you do indeed have spark @ the plugs.

Other than that Ya got me on this one! Probably something simple and overlooked.

bigodub93

ya i still have spark and i went over all my wiring again. i did not do the fuel rail check yet but i have been going off of my pressure gauge. also fuel filter and pump are new lees then 20 miles. and cel for about 2 seconds then it goes out, when i run the codes there is nothing.

bigodub93

because i do not have codes 4,8,9, does that mean they are working? is there a way to check ohms for these or anything.

bigodub93

ok i may have figured out what the problem. i have not checked into this but i hope this is whats wrong or im still stuck.

i pulled out my locash harness and wrote down pin by pin what wire goes from obd-0 pin to obd-1 pin. some of the stuff crosses right over but some things caught my eye. i have
b10 from obd-0 going to b11 on obd-1, my b10 is crank angle and b11 is cypp
b12 from obd-0 going to b12 on obd-1, my b12 is crank angle and b11 is cypm
c1 from obd-0 going to b15 on obd-1, my c1 is cylinder posistion and b15 is ckpp
c2 from obd-0 going to b16 on obd-1, my c2 is cylinder posistion and b16 is ckpm

what do these letters mean and am i right to think maybe these wires should be switched. please let me know thanks.

GhostAccord

lol that would probably be why your engine will not start.

This is what I cross referenced off some wiring diagrams (ECU Pin-out lists) that I have.

Cylinder Pos sensor (CYP)
OBD0 C1 to OBD1 B11
OBD0 C2 to OBD1 B12

Top Dead Center (TDC)
OBD0 C3 to OBD1 B13
OBD0 C4 to OBD1 B14

Crank Angle sensor (CKP)
OBD0 B10 to OBD1 B15
OBD0 B12 to OBD1 B16

bigodub93

man when i saw this i knew it wasnt right. i cant belive they made the harness with these mistakes. im just glad it wasnt something that i did because i felt like i didnt know ****. i just wish i didnt buy 650 bucks woth of diag. tools from snap on. but now i have them for life.

ill let you know if it starts up.