91 CRX Si cranks but won't start
12-05-2009, 05:37 PM
#1
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91 CRX Si cranks but won't start
Hi,
1991 CRX Si
-drove to gas station
-filled up (full tank; no top-off)
-engine cranks; but, won't start
-not throwing any codes
-towed home
-has spark (tested with spark tester set to proper gap, 0.040")
-pulled cleaned and regapped spark plugs to 0.040"
-pulled distributer (tested coil with ohm meter; main winding a little out of specification 0.7 ohms instead of between 0.3 to 0.5 ohms; the new one at the auto parts store measured exactly the same)
-swapped ignition switch for a known good one (same problem occurred)
A few possibilities:
-bad fuel (unlikely, many cars fueled up and drove away while I waited for tow truck)
-clogged fuel filter
-clogged air filter (no, I pulled it and car still wouldn't start)
-bad fuel pump
-no power to fuel pump (main relay?)
Any ideas on how to fix this problem?
Thanks,
ChrisS
PS, I don't have a wiring test harness. So, I cannot dig deeper into diagnostics.
PPS, I did some more testing per the 1991 honda civic/crx factory manual (p. 6-72; there's is power to fuel pump).
**one more question: in step #3 on the enclosed PDF, is the connector _still connected_ to the main fuel relay OR unconnected and shorted?
More status:
-pulled and tested main fuel relay (appears to be working
-8- -X- -4- -2- note: X marks no connector pin
-7- -5- -3- -1-
-#4=pos, #8=gnd >> continuity between #5 and #7 (works)
-#5=pos, #2=gnd >> continuity between #1 and #3 (works)
-#3=pos, #8=gnd >> continuity between #5 and #7 (works)
-disconnected ECU from wiring harness for a few minutes
-reconnected ECU
result:
car fires up, runs, and warmed up to running temp. (no problems idling)
** the only questions are:
-what scrambled the ECU so badly it required a full reset to make it work?
-how long will the car run reliably? >>maybe, it's time to look for a newer car and make this one a weekend only/second car.
(I guess next time, I could just pull the ECU fuse for 30 seconds and hope that clears the problem again.)
1991 CRX Si
-drove to gas station
-filled up (full tank; no top-off)
-engine cranks; but, won't start
-not throwing any codes
-towed home
-has spark (tested with spark tester set to proper gap, 0.040")
-pulled cleaned and regapped spark plugs to 0.040"
-pulled distributer (tested coil with ohm meter; main winding a little out of specification 0.7 ohms instead of between 0.3 to 0.5 ohms; the new one at the auto parts store measured exactly the same)
-swapped ignition switch for a known good one (same problem occurred)
A few possibilities:
-bad fuel (unlikely, many cars fueled up and drove away while I waited for tow truck)
-clogged fuel filter
-clogged air filter (no, I pulled it and car still wouldn't start)
-bad fuel pump
-no power to fuel pump (main relay?)
Any ideas on how to fix this problem?
Thanks,
ChrisS
PS, I don't have a wiring test harness. So, I cannot dig deeper into diagnostics.
PPS, I did some more testing per the 1991 honda civic/crx factory manual (p. 6-72; there's is power to fuel pump).
**one more question: in step #3 on the enclosed PDF, is the connector _still connected_ to the main fuel relay OR unconnected and shorted?
More status:
-pulled and tested main fuel relay (appears to be working
-8- -X- -4- -2- note: X marks no connector pin
-7- -5- -3- -1-
-#4=pos, #8=gnd >> continuity between #5 and #7 (works)
-#5=pos, #2=gnd >> continuity between #1 and #3 (works)
-#3=pos, #8=gnd >> continuity between #5 and #7 (works)
-disconnected ECU from wiring harness for a few minutes
-reconnected ECU
result:
car fires up, runs, and warmed up to running temp. (no problems idling)
** the only questions are:
-what scrambled the ECU so badly it required a full reset to make it work?
-how long will the car run reliably? >>maybe, it's time to look for a newer car and make this one a weekend only/second car.
(I guess next time, I could just pull the ECU fuse for 30 seconds and hope that clears the problem again.)
Last edited by ChrisS; 12-06-2009 at 01:42 PM. Reason: fixed for now (still not sure of the root cause)
12-09-2009, 07:40 PM
#2
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Ok when you get in the car shut every thing off so its quite and listen for fuel prime turn key and listen if you dont here the prime then replace your main relay its located on the driver side where the lower door hing goes but on the inside next to the coin tray its in there right about your hood relese cable.. You can tap it to get it to work or just get a diffrent one.. Also dizzy go bad.. Also could have a ground issue..
12-10-2009, 08:51 PM
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yes, the fuel pump spins.
I already pulled and checked the main fuel relay.
The distributer is fine. (no codes, coil checked out fine)
Update:
-cleaned the transmission ground and thermostat housing ground(main ground back to ECU)
Both appeared clean and shiny before I cleaned them with 320 grit sand paper.
-this weekend I'm going to resolder the main fuel relay(see link, below) to fix possible cold solder joints (I have had trouble starting in very hot weather and that's a symptom of cold solder joints in this relay.)
http://techauto.awardspace.com/mainrelaydetails.html
-the only other thing I'm thinking of doing is replacing the car's main ground cable (battery neg. to body to transmission)
Other than that, the car is running pretty well and hasn't had any problems starting.
I already pulled and checked the main fuel relay.
The distributer is fine. (no codes, coil checked out fine)
Update:
-cleaned the transmission ground and thermostat housing ground(main ground back to ECU)
Both appeared clean and shiny before I cleaned them with 320 grit sand paper.
-this weekend I'm going to resolder the main fuel relay(see link, below) to fix possible cold solder joints (I have had trouble starting in very hot weather and that's a symptom of cold solder joints in this relay.)
http://techauto.awardspace.com/mainrelaydetails.html
-the only other thing I'm thinking of doing is replacing the car's main ground cable (battery neg. to body to transmission)
Other than that, the car is running pretty well and hasn't had any problems starting.
12-12-2009, 11:48 AM
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it will happen again.
reason why it died is the main relay overheats
reason why it started is the main relay had already cooled down.
new main relay is required.
you dont need to reset the pcm
reason why it died is the main relay overheats
reason why it started is the main relay had already cooled down.
new main relay is required.
you dont need to reset the pcm
12-13-2009, 09:59 PM
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I pulled main fuel relay and did a through inspection of the solder joints per the link in my previous post.
Three or four solder joints were pretty bad. Two others had very fine cracks.
Cleaned with solder wick (thin braided copper ribbon that wicks up solder when heated and applied to solder joints) and re-soldered all solder connections on main fuel relay.
Now, every time I turn the key from ACC to ON I hear the fuel pump spin.
I think, the problem is fixed permanently.
If you don't know how to solder, just buy a _new_ main fuel relay for about $50 _or_ take your old one to an electronics repair shop and have them re-solder all the joints (maybe, $15?).
Take Care,
ChrisS
Three or four solder joints were pretty bad. Two others had very fine cracks.
Cleaned with solder wick (thin braided copper ribbon that wicks up solder when heated and applied to solder joints) and re-soldered all solder connections on main fuel relay.
Now, every time I turn the key from ACC to ON I hear the fuel pump spin.
I think, the problem is fixed permanently.
If you don't know how to solder, just buy a _new_ main fuel relay for about $50 _or_ take your old one to an electronics repair shop and have them re-solder all the joints (maybe, $15?).
Take Care,
ChrisS