Car dies as soon as it hits 0 vacuum

[tehzack]

Well I finally got this rig runnin again and it was running great for like 2 days. All of the sudden the car started dying as soon as it hit 0 vaccum on the boost gauge. It drives fine in vacuum, but as soon as it begins to transition into boost it just feels like the engine shuts off until it goes back into vacuum. I've looked for obvious stuff I can think of like vacuum leaks. Any ideas on what I can check? Btw, my car is 87 widebody w/ 89 ignitor and ecu.

[jisleyjr]

How is the secondary injector? Sounds like lack up fuel.

[tehzack]

Okay so I've been doing a lot of reading on symptoms of a bad secondary injector. Full throttle dying: Check. Quick chop of the throttle dying: Check. Won't go into boost: Check. I'm about 70% my secondary injector pwnd itself here. Is there a way I can test this to be 100% certain? Edited March 9, 2010 by tehzack

[boostdquest89]

Secondary inj....switch ur clips and it should idle on ur secondary if its working correctly.

G/L

Chad-

[dstar88]

pull the secondary injector clip off.. see if you can start the car. if the car starts as normal and iddles fine then good. Turn the car off, then pull the primary injector clip off and plug it into the secondary injector, then try to start the car again. If the car starts and iddles a little loppy and spits some black smoke out, then that would show that at least your secondary injector is spittin some fuel out and is at least working.

 

this could mean that your secondary injector clip could be bad or messed up somewhere in the wiring. it could also mean other things as well. like the injector balast or what ever its called could be going bad or something allong those lines.

 

If the car does not start with the primary clip plugged into the secondary injector. Then pull the OVCP off and see it its even firing. the car should still start and at least iddle really crappy if the secondary injector is working. if the engine does not start then there may lye your problem., It may lead back to the secondary injector clip, the wiring for that clip, or the injector., it could also be other things.. but thats where i would start.

 

 

 

 

Daniel

[dstar88]

fraken thing wouldnt post what i put till now.... >:-( ... oh well.. it worked finaly.. lol

 

 

 

 

Daniel

Edited March 9, 2010 by dstar88

[tehzack]

So I just went out and performed said procedure. I couldn't pull the OVCP and look while cranking since i'm tinkering with this thing Hans solo at the moment. Anywho, primary injector plugged in and secondary unhooked car cranks idles fine. Plugged primary injector clip into secondary injector and car wouldn't crank or do anything.

[Hoosierquest]

So I just went out and performed said procedure. I couldn't pull the OVCP and look while cranking since i'm tinkering with this thing Hans solo at the moment. Anywho, primary injector plugged in and secondary unhooked car cranks idles fine. Plugged primary injector clip into secondary injector and car wouldn't crank or do anything.

Sounds like you found your problem. Bad sec. injector.

If I was you I would go ahead and start looking into the delphi injectors. I know there are people here that say they dont have the same spay pattern as stock and they are no good but I use them and they work fine. Also its not that easy anymore to find a good non leaking/broken injector. H

However the delphi's do require some machineing to the throttle body but I did mine with a drill press then cleaned up with some fine grit sand paper and they have never had a leak.

[tehzack]

I just went and swapped in another injector from a guy that changed his working injectors out for delphi's. Still no dice. the injector still won't spray. He (BC_99 on here, great guy btw) also cleaned my injector clips while he was at it, but they still look pretty terrible. I'm gonna try replacing my injector clips and see if that works. If not then I suppose i'm back to the drawing board. Just as sort of an idea pool... what are the reasons the secondary injector wouldn't work? So far i've gathered that I could have just run across 2 bad stock injectors (not crossing out that poss. since they are all at least 21 years old at this point), bad injector clips, anything else? Edited March 10, 2010 by tehzack

[mikec]

Injector circuit is:

 

battery + post --> ECI fusible link --> ECI relay -->ballast resistor --> injector --> ECU --> Ground.

 

The ballast resistor has one input and two outputs - one output for each injector. The ECU grounds the injector's other connection prong to trigger/fire the injector.

 

With the engine idling on the primary injector, unplug the connector to the secondary injector. Get a multimeter (or a plain voltmeter, analog or digital) and set it to a 12 to 20 volt DC scale. Connect the black/- probe to the battery "-" post and use the red/+ probe to check the contacts in the secondary injector's wire harness clip. One of the two contacts should have +12volts on it if the wiring & ballast resistor are working. We know the ECI fusible link, ECI relay, etc. are working if the engine idles - those pieces also power the primary injector of course. So if you find +12volts on one of the wires going to the secondary injector then the bug is:

* injector

* lousy connection between connector and injector

* wire from the connector back to the ECU

* the ECU itself

* The injector is plugged/jammed so even if the electrical parts are working fine gas still can't get through it.

 

Shut the engine off. Set your multimeter to the x1 "ohms" or "resistance" scale. (or "200 ohms" scale on digital meters) Touch the meter's probes together, the meter should swing to zero ohms. Now touch the meter probes to the flat metal tangs of the secondary injector itself. The meter should read ALMOST zero ohms this time... somewhere around 2 to 3 ohms. If the meter doesn't read anything then either you have a totally lousy connection or a fried injector.

 

mike c.

[tehzack]

So if you find +12volts on one of the wires going to the secondary injector

 

 

Secondary injector clip has power at idle

 

Shut the engine off. Set your multimeter to the x1 "ohms" or "resistance" scale. (or "200 ohms" scale on digital meters) Touch the meter's probes together, the meter should swing to zero ohms. Now touch the meter probes to the flat metal tangs of the secondary injector itself. The meter should read ALMOST zero ohms this time... somewhere around 2 to 3 ohms. If the meter doesn't read anything then either you have a totally lousy connection or a fried injector.

 

Primary injector reads 3 ohms. Secondary injector doesn't read.

 

 

 

Okay, so i'm assuming since the injector is getting power, and it failed the ohm test that the problem is in the injector itself.

Edited March 10, 2010 by tehzack

[rosengrant826]

We are both in the same boat, I just checked my injectors and both are good so are the clips. After talking with dmyers and Starquestjoe we came to beleive that my bov maybe leaking. I have the mookeeh ssv one. has anyone tried these?

[mikec]

Okay, so i'm assuming since the injector is getting power, and it failed the ohm test that the problem is in the injector itself.

If the injector didn't show electrical continuity (you did use the resistance function of your meter, not a voltage setting, right? Some folks have made this mistake) then the injector is burned out. It should be just a couple of ohms.

 

mike c.

[tehzack]

Yessir. The meter was set correctly.

[TainterRacing]

That sounds like you have a leak in the ic pipes go over there very carefully might only leak under boost tighten all clamps.

[Indiana]

These motors, especially with OS valves will pull much more vacuum at idle and while under load before boost and you can easily suck open a BOV by just rev up the motor in neutral. A stock DSM BOV sucks open if you rev this motor in neutral. If it doesn't your cam timing is screwed up. There will be enough volume and low enough pressure to do this so you should check this as a possibility of the motor hesitating when you try and rev it up and worse, while you are cruising around not under boost the BOV is actually sucked open and blowing out the air and the fuel is dumping in and your air/fuel is rich as hell. A BOV needs to have a strong spring that CAN NOT be opened easily, there is no reason for it to open for noise if you have one it is there for a purpose and that's after HIGH boost pressure, not 5 or 10psi but 15 or 20psi and its going to briefly open when the throttle is closed and that same vacuum you see at idle gets enough volume, same as you just rev it up in neutral if the spring is weak, to pull it open BUT the boost pressure will help push it open also. Face it, most BOVs you see online for sell are crap, you can't get a decent BOV for under 100-125.00 and if its not adjustable or you can't change the springs in it its a cheap piece of Chinese crap and for those low boost pulls and for noise that isn't helping your turbo not spool again if its blowing off at 5psi. There are supposed to help your turbo stay spooled up, meaning the shaft spinning say 100k+ so you don't have to start over. This is a part of quick WOT shifting NOT "normal" driving. You are having the BOV open too many times and just wasting gas but most BOV are about letting someone hear it, big deal. Those are RICER parts if that's all they are good for. If you have a large turbo then it likely you spent some money on it and do not have a whimp BOV if you think your should open all the time. Your turbo isn't a weak baby fragile thing its not going to break if you don't let every single shift cause a BOV to make a whoosh sound and for those lower boost level pulls you letting the pressure out means you start over and you aren't driving hard anyway so why again is this happening? If you can't tell and suspect your BOV is leaking, just take the reference hose off of it.

 

Put a flashlight battery to your secondary injector you think isn't working or use two wires from your battery in your car but wire in a light bulb or use a test light and just strike the wire to the battery post and listen to see if this injector clicks. If it clicks and or you can feel it trying its not dead its stuck but if it clicks its working.

 

I've seen intercooler couplers that are placed at the tubing and have the clamps on but the coupler is just touching the end and if you pulled on them you would find out they are not connected.

 

If you have a 1G MAF, make sure the plug isn't on upside down. The plugs with the end cut out so they stick on the stock wiring harness, you can put that plug on upside down so look at the locking tab on the harness end and look on the MAF where the locking tab was filed/ground down and make sure those are on the same side.

 

Unplug the ECU and plug it back in and make sure you didn't pull one of the wires out. The two injector wires are yellow w/blue stripe and yellow w/black stripe and they are in the smaller plug opposite the side with the locking tab.

[tehzack]

It was the secondary injector. I'm running a 1g talon bov and it seems to be doing okay I guess. It only really makes any noise if the car goes above 10psi. Anywho, the injector started randomly working again yesterday, then stopped again after I replaced my injector clips this afternoon. I took it off, sprayed it with brake cleaner, and whacked it with a screw driver a few times and it started working again. I know how incredibly ghetto/hack that sounds, but it really did start working again after that lol. But my new set of injectors should be here tomorrow or Tuesday so i'm driving the truck til then for good measure. Thanks for all the help guys.

[BC_99]

glad you got it worked out. LMK if I can ever help you with anything else.

 

BC_99

[polarisman14]

Wish I knew about this when I had my 88 before. I assumed it was the turbo (don't flame me too hard, it did have a LOT of shaft play and I figured it was getting jammed against the compressor sidewall) but this makes a lot more sense. Useful thread, thanks.