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I am not getting any vacuum at my wastegate actuator. I have 25 points of vacuum from my vacuum pump.
I have 13.85 volts at my selinoid electrical connector. I ran 2 wires from my battery to the selinoid and then I got 20 points of vacuum at my wastegate actuator...so I know my selinoid is working and I know my lines are good.
All I can think of is am I not getting enough amperage at the selinoid using the electric connector....because it all works if I run wires from my battery right to the selinoid...
I'm stumped....
phantom309
07-15-2011, 18:56
The solenoid varies the vacuum,. it's not an 'on-off' switch,.
Nick
If I have 13.85 volts at the selinoid it should be "on" and letting vacuum thru to the actuator. From what I've searched on here I should get 15-20 points of vacuum at the actuator at idle.....but I am not.
The solenoid is controlled by the PCM on the ground side. It pulses the ground on and off. the amount of time spent on relative to off controls the vacuum. Measure with a dwell meter on the ground side, like an old points ignition. A common failure mode is the solenoid failing to respond fast enough to the pulsing. Also, ensure the vacuum pump is connected to the solenoid port with the restrictor in it.
John...thanks for the advice. I will have to borrow a dwell meter from somewhere this week and test the ground wire. Can you tell me exactly how to test it and what I should see on the meter...it's been many years since I used a dwell meter.
Also, my truck is throwing codes 31,32,33,35,36. I have replaced the MAP sensor on the intake and disconnected both batteries to erase the codes...but they came back....does this have anything to do with my wastegate issue??
Thanks again.
OK..finally got a chance to test my pcm and selinoid. Couldn't find a dwell meter anywhere so I used a probe light.
I have 12.74v on the pink wire at the selinoid with the key on and or with engne running.
If I ground the yellow wire at the selinoid while the truck is running then everything works fine...I get wastegate actuator arm to pull stiff.
If I probe light the yellow wire at the selinoid it is just dim while the engine is running.
I checked volts on the yellow wire while engine was running and it jumped around from 5v, 9v, 12v.....
So...is it my PCM?? or is the new selinoid bad (not switching fast enough)?? or is the new MAP sensor screwing something up??
Many VOM's available today have a setting called "duty cycle". Same thing.
Anyone older than 50 who works on cars should have a dwell meter.
I finally found a dwell meter...I put the green lead on the yellow wire and the black lead on the pink/other wire. I started the engine but the needle on the dwell meter never moved.
So I guess my PCM is not pulsing the pink wire to ground. I have grounded the pink wire and the system works great. So do I replace my PCM? or could the new MAP sensor I put on be causing the PCM not to ground the pink wire?? or is there another sensor that could be causing the issue??
IIRC you don't have the dwell meter connected properly.
I think power needs to pass through a load but I am unsure about that.
When using a dwell meter for a points ignition you connect 1 end to ground and the other end to the negative coil wire.
When the meter measures in degrees of crankshaft rotation how long the points remain closed.
For your purposes I would try piercing the ground wire with a pin and connect the dwell meter to ground on 1 side and the pin on the other with the soolenoid still hooked up.
I could be wrong but I suspect current flow through the solenoid needs to happen otherwise the dwell meter is the only thing between connecting power to ground which is never good with electronics.
Since I have never tried this test I hope someone who has can confirm or reject the way I think it might need to be connected.
Ok...well I'm confused. How do I need to hook the dwell meter up? Does the black clip go on the ground of the battery and the green clip go on the pink selinoid wire?? or ..??
Codes 35 and 36 are response time short and long and should not generally show up at the same time.
I am suspect that you may have a bad ground at the RH rear of the engine where the harness grounds are located.
A bad battery feed or battery ground can cause this too.
Be sure you have 14+ volts with the engine running at both batteries and the chassis feed lug.
If your voltage is low at one battery, fix it.
Too many codes to go jumping to conclusions just yet.
Multiple codes that all of a sudden pop up can be ground related.
The fact that things sort of got better when you probed the one lead with your test light suggests that it may be a ground issue.
Check all the grounds on the batteries and the engine to harness and chassis to body, etc.
Missy
Take the connector off of the wastegate solenoid. Probe the connector with a volt meter. One side should show battery voltage (key on). Connect the red or + lead of the dwell meter to the other wire (not battery voltage) and the black or ground wire of the meter to the engine block ground. Re-attach the connector and crank the engine up. Read Dwell on the 4 cylinder scale if you have that, or read the duty cycle in %.
I checked all my grounds at the battery to fender..grounds at both sides of the intake from each battery....ground at rear of engine to firewall...firewall to frame...
I have 14.47v at battery with engine running...2 new batteries this week too.
I unplugged both wires to the solinoid and had 12v on the pink wire with key on. I stripped some insulation off the other wire (yellow) and put the + clamp of the dwell meter on that wire...I put the - clamp of the dwell meter on the ground wire on the intake. I plugged the connector back into the solinoid and started the engine. The dwell needle didn't even move. So...??
Well I haven't heard from anyone...so I ordered a PCM from GM and it will be in tuesday. With this being a 1995 OBDI system, do I need to have GM program the PCM or is it just plug and play??
Well the new PCM didn't fix the solenoid problem....buying a Heath Turbo Master. Got to have this truck up and running.
Maybe someone can answer this for me... I replaced the MAP sensor on the intake and the sensor GM ordered for me didn't fit the connector...so they sold me a new connector to splice in. If I got one of the 3 wires wrong on the connector would it have anything to do with the turbo not working?? And can someone tell me which color of wire should be going to which plug on the MAP sensor....
DmaxMaverick
08-16-2011, 21:28
It could have everything to do with it. Return your harness to original, and get the correct sensor.
I don't have the wire connector anymore becuase it was broke to begin with....and I ordered the MAP sensor thru GM and they used my VIN to order the part but then my original connector wouldn't plug in so the GM parts guy called GM and they said it was an updated part and I would need the new connector.
I've checked my local salvage yards for a 6.5 but no one has any parts...can someone at least tell me which wire color goes into which plug on the MAP sensor?? just in case I did that wrong....
And...if I unplug the MAP sensor and leave it unplugged...and unplug the negative posts on the batteries would the PCM reset to a default value for the MAP sensor and then my turbo would work if it's the MAP sensor causing the wastegate solenoid not to pulse???
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