Starting issue, where to start diagnosis?
#1
Starting issue, where to start diagnosis?
Hi Guys,
I recently replaced the head gaskets on my '90 RR. It went back together easily enough, but I now can't get it to start. It cranks fine, and it has spark on all cylinders, however, I'm not sure how strong the spark is. So my guess would be lack of fuel... where would I start going about checking? You can't really easily take out an injector, but I guess if I need to I can. I just didn't know if there was something I should check first before I start blindly stabbing. I'm 99% sure everything is connected correctly, albeit the harness for the injection system isn't in great shape. So... I'd really appreciate any and all help and suggestions. Thanks in advance! -Ted
Also... if it helps, when you have it in the ON position, there is a clicking noise under the passenger side of the dash. It goes away after about 30-45 seconds, but will sometimes start clicking again if you crank it. Is this a fuel pump relay, or...? I don't remember it doing that before, but it wasn't a car I drove often, so It could have very well always done that, just don't remember.
I recently replaced the head gaskets on my '90 RR. It went back together easily enough, but I now can't get it to start. It cranks fine, and it has spark on all cylinders, however, I'm not sure how strong the spark is. So my guess would be lack of fuel... where would I start going about checking? You can't really easily take out an injector, but I guess if I need to I can. I just didn't know if there was something I should check first before I start blindly stabbing. I'm 99% sure everything is connected correctly, albeit the harness for the injection system isn't in great shape. So... I'd really appreciate any and all help and suggestions. Thanks in advance! -Ted
Also... if it helps, when you have it in the ON position, there is a clicking noise under the passenger side of the dash. It goes away after about 30-45 seconds, but will sometimes start clicking again if you crank it. Is this a fuel pump relay, or...? I don't remember it doing that before, but it wasn't a car I drove often, so It could have very well always done that, just don't remember.
Last edited by AustinMiniMan; 01-17-2010 at 05:59 PM.
#2
crank it over a few times and then pull out a spark plug if you dont smell gas then you dont have fuel
You could also spray some ether into the intake no more than a 2 second burst and then crank it over see if it wants to fire if so then your injection system isnt working, time to trace the wires and make sure none of them are shorted
You could also spray some ether into the intake no more than a 2 second burst and then crank it over see if it wants to fire if so then your injection system isnt working, time to trace the wires and make sure none of them are shorted
#3
#5
Thanks. Where is the camshaft position sensor plug located? I think I got everything plugged back in but it never hurts to check individually. Is there a place to test the fuel pressure, or do I just disconnect the line before it goes into the fuel rail? I have a '92 parts RR, so if I don't get anywhere with the other two tests I'll swap out the coils and go from there. Although it ran great before hand, and other than disconnecting it, I didn't touch the coil. But you never know when something wants to give out.
I can't believe I didn't think to take a spark plug out and smell for gas. I don't know... I'm used to working on old Minis and Volvos; when I get into the complicated stuff I tend to get kind of light headed and forget the basics. It's all the same in the end, I suppose... just more wires. Lots and lots more wires. -Ted
I can't believe I didn't think to take a spark plug out and smell for gas. I don't know... I'm used to working on old Minis and Volvos; when I get into the complicated stuff I tend to get kind of light headed and forget the basics. It's all the same in the end, I suppose... just more wires. Lots and lots more wires. -Ted
#6
you can check to see if you have power at the pump alot easier then a fuel pressure test. the relays underneath the passenger seat for the fuel pressure and fuel injection do like to go. try swapping them if you have no fuel. jump the relay if you have to get direct fuel and start it up to see if it will start.
#7
All those sugestions for checking to see if you have fuel pressure will work, here is another. Just push in the pin on the schrader valve that looks like the bike tube valve on the fuel rail. empty it out so no more comes out. Then try to turn over the engine, if the pump works then it will have pushed fuel back to the valave and will squirt out when the pin is pushed again, you will ned something else if the pressure if off but at least you will know if there is fuel getting up there.
If you have spark, even if it is weak then your crank positioning sensor is working, that is the only way the ecu knows where the crank is and to send spark in the first place.
If your pump is not working check the fuse first, may be as simple as that.
While it may not cause it to not run double check the MAF sensor plug and make sure you did not miss attaching it once everything was done.
Cars are fairly simple, air, fuel and spark, that is where to start.
If you have spark, even if it is weak then your crank positioning sensor is working, that is the only way the ecu knows where the crank is and to send spark in the first place.
If your pump is not working check the fuse first, may be as simple as that.
While it may not cause it to not run double check the MAF sensor plug and make sure you did not miss attaching it once everything was done.
Cars are fairly simple, air, fuel and spark, that is where to start.
#8
#9
#10
Alright guys... thanks for all of the advice so far. Here's where I'm at. I tested the two relays under the seat, and they work. The four relays under the kick plate in the passenger foot well all work as well. They all have acceptably low levels of resistance. I jumped the relay for the fuel pump, and it still wouldn't start. The relay in the kick panel is still clicking on and off while the vehicle is in "ON" or "START." It clicks pretty rapidly for at least 30 seconds. It's the 2nd relay from the back; the only one under there with a black terminal block. What does this relay do? Is it supposed to click like that?
What's next? Assume the fuel pump is bad? I'm having a bit of a logical problem, in that all of my theories assume that I didn't do anything wrong when replacing the head gaskets. I.e, the vehicle started fine, then it sat in the garage for 2 weeks while I did the heads, and now it won't start. Assuming something else randomly broke while it was sitting seems a little suspicious to me, but then again, I can't think of anything under the hood that would have caused these symptoms.
What's next? Assume the fuel pump is bad? I'm having a bit of a logical problem, in that all of my theories assume that I didn't do anything wrong when replacing the head gaskets. I.e, the vehicle started fine, then it sat in the garage for 2 weeks while I did the heads, and now it won't start. Assuming something else randomly broke while it was sitting seems a little suspicious to me, but then again, I can't think of anything under the hood that would have caused these symptoms.