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david craig
david craig,
Category: Pontiac
Satisfied Customers: 1927
Experience:  owner/mechanic at 3D Automotive
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Just changed out all 6 of the fuel injectors in my Pontiac

Customer Question

Just changed out all 6 of the fuel injectors in my Pontiac Aztek. Everything is connected but now the engine is knocking and when the key turned it does not start unless I give it gas, something inside shaking or creating a knocking sound. I ordered remanufactured fuel injectors from ebay.
Submitted: 1 month ago.
Category: Pontiac
Customer: replied 1 month ago.
The fuel injectors were Genuine Delphi, I have drained the radiator, so I have very low coolant, I also replaced the air intake tube, I bought that from a local junkyard but looks to be in very good condition.
Expert:  david craig replied 1 month ago.

Hi Im David, what was the original problem that led you to replace all of the injectors?

Customer: replied 1 month ago.
Hey David! Ok so I did this as a preventive maintenance, Engine did not have much power, so I Changed spark Plugs, & fuel pump last month, it did not make much of a difference so I decided to change out Fuel injectors. So here is the update: I went out an started the car again, and the knocking seems to be reduced, but there is high pitch whine. So its not knocking anymore, I drove just 1/4th of mile around my Neighborhood and seems to be driving fine. On park there is whining noise, O reverse no noise, On drive the noise come back again like a high pitch whistle. I drove it one more time and when I slowed down to make U-turn car turned off, so I restarted and started fine. I drained the coolant through Lower radiator hose before removing the injectors, so I have very Low coolant, I put back may be 1/2 of what I drained from removing lower radiator hose.
Customer: replied 1 month ago.
I may have to drive it a while, I need to get more anti-freeze from the store before I can drive.
Customer: replied 1 month ago.
also have engine check light turned on
Expert:  david craig replied 1 month ago.

you have a code reader?

Customer: replied 1 month ago.
No don't have one I may have to take it up to Autozone.
Expert:  david craig replied 1 month ago.

if you could that would be great. gives a clear path.

Customer: replied 1 month ago.
I put GM Dex-cool anti-freeze in the car by pouring into the radiator and also by opening the two bleed valves drove to Walmart earlier today, and then on my way to Autozone, engine sign completely disappeared. The issue that I am having now is the whistling sound coming from I believe to be under the intake manifold cover of the engine and car RPM jumps while parked and also car only starts if the gas pedal is pressed down while turning the ignition. I have to give it gas when trying to start. At this point I am not sure if one of the remanufactured injectors I purchased may not be good?
Expert:  david craig replied 1 month ago.

sounds like a vacuum leak. get a can of carb cleaner and start spraying around any and all vacuum hoses/fittings/connections....also spray around the base of the intake. listen for an rpm change and youve found your leak.

Expert:  david craig replied 1 month ago.

going out for a while, will be back in a few.

Customer: replied 1 month ago.
I am about to go pick that up. I did change three vacuum hoses during the Fuel injector change . I purchased it from the local salvage yard, they were in decent condition. The hose from PCV Valve to the Throttle Body to a sensor, Hose from the sensor (MAF Sensor?)on the air intake hose to the back part of the engine, and another hose which goes from the engine to the MAP sensor. I detached the hose that connects to the MAP sensor while idling, pulling it did not make any difference at all, I am thinking whether that hose is the issue. Anyway I am going to purchase the Carburetor fluid and see if it can be detected that way.
Expert:  david craig replied 1 month ago.

im back, any update?

Customer: replied 1 month ago.
I just got back home from Autozone, I bought Carburetor cleaner I waiting for the car to cool down, should I worry about any fire hazard while spraying it. also the engine light came back on after I removed the air intake and put it back on. These are the codes: P0101, P0107,P0300,P0171
Expert:  david craig replied 1 month ago.

you dont need the engine to be cool. just dont use brake parts cleaner. as far as the codes, just erase them by disconnecting the battery for 10 minutes and then reconnect it.

Expert:  david craig replied 1 month ago.

unless you have a code reader

Customer: replied 1 month ago.
I think I found a vaccum leak when I sprayed the rpm did make the difference in sound. Here is a photo, I am pointing toward the hose with a rod. other end of the hose is attached to the PCV Valve
Expert:  david craig replied 1 month ago.

yes, that plugs into the back valve cover. its a very common problem area, because it falls out easily

Expert:  david craig replied 1 month ago.

any luck?

Customer: replied 1 month ago.
Actually I don't think that is the one attached to the back of the engine. The hose attached to the back of the engine connected to the Air Intake tube next to MAF sensor. That one looks fine. This hose starts at the PCV Valve, mid portion of the hose goes into the throttle body and the other end he is what I shown in the last picture, it looks to be some sort of a sensor it is going into, I replaced the tube still no luck, now there is no leak in that area.
Expert:  david craig replied 1 month ago.

that must have went to the map sensor then

Customer: replied 1 month ago.
I also doubt that the throttle body is loose. I removed 1 bolt top left 13" and a Nut diagonally across from it also 13" then another small nut that hold the bracket shown in the picture under the throttle body, I put them back on, but according to my notes there was one more bolt for throttle body, I was left with one bolt I am not sure where it goes I don't see any other place it can go on the throttle body.
Expert:  david craig replied 1 month ago.

those 2 bolts go on that bracket right below your hand

Customer: replied 1 month ago.
I got those on without a problem, its the throttle body somehow I was left with one extra bolt.
Expert:  david craig replied 1 month ago.

there are 4 bolts for the throttle body. one is actually a stud with a nut on it.

Customer: replied 1 month ago.
may be its the bolt 1 bolt top left, stud with a nut diagonally across, 3rd one which hold the bracket on the picture on to the throttle body and its at the bottom, where does the fourth one go?
Expert:  david craig replied 1 month ago.

the stud one goes bottom front or rear to hold the bracket for the water line

Customer: replied 1 month ago.
Yea that one is good, I have that one tightned.
Expert:  david craig replied 1 month ago.

show me the one you have left

Expert:  david craig replied 1 month ago.

this shows only 2...hmmmm

Expert:  david craig replied 1 month ago.

did you put a new gasket on for the throttlebody?

Customer: replied 1 month ago.
Well I did not remove the throttle body, I just removed the screws to open the engine cover, as shown in a video, but I did not separate the throttle body itself from the engine cover. Here is the bolt I am not sure if it came from that throttle body area according to my notes it did but I could be wrong. Here is the Pic.
Expert:  david craig replied 1 month ago.

thats not a throttle body bolt. looks like a bolt that hold on a bracket somewhere

Customer: replied 1 month ago.
After replacing the Fuel injectors I replaced the Gaskets under the engine cover could it be that the top engine cover is not sitting correctly on the gasket, should I have put something on those intake gaskets like a paste or grease, I put them on dry, if that gaskets is not sitting correctly would that cause this rough idle.
Expert:  david craig replied 1 month ago.

if it didnt fit flush and didnt feel right, if it rocked a little, then you need to pull it and make sure nothing got in the way and that the gaskets didnt move.

Customer: replied 1 month ago.
Also only other thing I can think of is the Map sensor, there is clip that plugs into the Map sensor, it clicks and snap into place, I think the part were it clicks on is broken, so its pushed in all the way but does not snap and click.
Customer: replied 1 month ago.
There is a chance that those gaskets could have moved while I was adjusting the cover it did move so I had to reseat them again.
Customer: replied 1 month ago.
I am thinking it is those gaskets might have moved while I was placing the engine cover, I have to take everything out again including coolant draining. It will be easier since its the second time. Is there anything I can purchase to sort of paste the gaskets on so they wont move and also I am having trouble with refilling coolant.
Expert:  david craig replied 1 month ago.

dab them here and there with black gasket maker to hold them in place

Customer: replied 1 month ago.
I drained the coolant by removed the lower radiator hose and collected in a pan. When I refilling it through the radiator it never let me put the whole thing in, the radiator get filled so quick but there isn't much in it. I even loosen the two bleed valaves as mentioned in the user manual, still does not help, is there a trick to it.
Customer: replied 1 month ago.
I will get the gasket marker.
Expert:  david craig replied 1 month ago.

add it back in til its full. start the engine rev the throttle it will suck down then add more..etc...

Expert:  david craig replied 1 month ago.

please accept the answer and leave a 5 star rating for me if you are satisfied with my assistance. you can still ask for advice afterwards. thank you .

Customer: replied 1 month ago.
How do I Rev the throttle. I will take care you, but so far I have not found a solution.but I thank for trying. I wil get back withyou an update
Expert:  david craig replied 1 month ago.

how do you rev the throttle???? you press on the gas.

Customer: replied 1 month ago.
I have seen people doing that by pulling on the string near the throttle, I thought that's what you meant when you said rev the throttle lol! I assumed you would give it some gas otherwise. Ok no problem.
Expert:  david craig replied 1 month ago.

oh ok. sorry

Customer: replied 1 month ago.
No problem. So here is whats going on. I removed everything again, One of the nuts at the bottom of the throttle body that holds the bracket also was loose, so that could have been the problem. But I took the top cover off also just to make sure and used some gasket sealer. So When I was trying to put back the top engine cover two of the bolts seems to be loose and cannot be tightened to the torque. and when tightening another bolt part of the cover cracked and unfortunately all those bolts are in the front of the engine. Cracked part exposes the intake, so I have no choice but to replace the cover.
I need to know why the bolts are loose, and cannot be tightened? What can I do about it? and also do I need to replace the lower intake as well, because the bolts are being tightened on to the lower intake?
Customer: replied 1 month ago.
OK I think I see the problem, Lower intake bolt area is cracked, I may have overtightened it please see pics. I also took the throttle body out to clean it but the string cap broke also, so I am very much having a bad day, but the good news is Lower intake and upper intake are sold in the local salvage yard so I can get them both. Please see attached photos. Thanks.

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