CK5 Network
Become a member of the largest online community for Chevy K5 Blazer, Suburban and C/K series truck owners!

TBI problems after changing injectors

70jimmy

3/4 ton status
Premium Member
GMOTM Winner
Joined
Mar 3, 2000
Posts
7,198
Reaction score
2,102
Location
Released from Pueblo, told I belong in Southpark
Engine is from a 1993 Suburban that I put in my 70 Jimmy back in like 2008. I have been fighting what I think is a fuel problem for a while now. So I decided to change injectors. I changed the injectors and flubbed up and didn't put the little rubber owl eye things back on top of the injectors and put it together and went to start it. When I hit the ignition switch it just went clunk. Then after thinking about it I remembered the little rubber pieces and put them on. Tried to start it again and it turned over like normal but no start. I tried a few times and it turned over well but didn't try to start. I poured a little gas down the throttle body and no change, so I am thinking more of a no spark condition.

First thought is ignition control module. I bought one but when it stops raining I will put it in. Looking for ideas on what to check and how to check it. I do have a voltmeter, just not that familiar with diagnosing TBI. I ordered a manual for that year since I didn't have any yet that covered the 93.

Thanks for the help!
 

bp71k5

3/4 ton status
Premium Member
Joined
Mar 31, 2006
Posts
8,470
Reaction score
2,436
Location
Knoxville, TN 37922
If it’s not squirting fuel, it won’t fire the spark either. Make sure the injector connectors are not broken or slipped off.
 

70jimmy

3/4 ton status
Premium Member
GMOTM Winner
Joined
Mar 3, 2000
Posts
7,198
Reaction score
2,102
Location
Released from Pueblo, told I belong in Southpark
I will order the tool tomorrow and I have checked the injector connectors and they look good and are well attached, wires to them also look good.

Wifey pulled the rig backward while I steered with the mini blazer, that looked funny. Then I pushed it forward while she held the wheel so we could get the car in the garage.
 

Wes Harden

3/4 ton status
Premium Member
Joined
May 28, 2005
Posts
5,406
Solutions
1
Reaction score
5,741
Location
Lake Havasu City AZ
how long between the clunk crank, fixing the flub, and attempting to start? Did it flood ?
 

dyeager535

1 ton status
Premium Member
Joined
Dec 13, 2000
Posts
29,888
Reaction score
1,532
Location
Not Roy WA
I'd seriously consider not wasting time on the module. If it's indeed something in the distributor, and turns out to be pickup coil, you will have to pull it back out, spend more money to replace another part, and maybe spend more than just getting a complete parts store cheapy distributor.

Need to figure out the no start reason first however. No spark, no injector pulse. Wiring, power feed, failed component, etc.
 

6872xtc

make mine modified
Premium Member
GMOTM Winner
Joined
Sep 16, 2008
Posts
7,758
Reaction score
8,007
Location
Palisade,Colorado
I had one of the new Chinese replacement distributors that lost the module in less that 10 miles. I barely made it home to put the old Delco one in.

I agree that there must be something in the electrical system wrong to cause the no crank episode. The injector plug seals aren't tied into the starting circuit, as far as I have seen. Possibly even contributing to the crank, no start now.
 

1-ton

1/2 ton status
Premium Member
Joined
Apr 17, 2004
Posts
4,857
Reaction score
1,977
Location
Las Vegas, Nevada
If you had a remote starter switch you could spin the engine while looking at the TBI (with key in ignition "on'' position). If you see the TBI shoot a spray of fuel that means the injectors are working, and so is the control module that sends a pulse signal to the ECM to shoot a shot of fuel into the engine for open loop cold start.
 

dyeager535

1 ton status
Premium Member
Joined
Dec 13, 2000
Posts
29,888
Reaction score
1,532
Location
Not Roy WA
You can also run a test bulb with leads long enough to see from the cab to make sure the injectors are being commanded to work.

Easy to make with a bulb from the cluster and long wire.
 

bp71k5

3/4 ton status
Premium Member
Joined
Mar 31, 2006
Posts
8,470
Reaction score
2,436
Location
Knoxville, TN 37922
Can also just take the air cleaner off and have your wife try and start it while you watch the injectors spray or not.
 

dyeager535

1 ton status
Premium Member
Joined
Dec 13, 2000
Posts
29,888
Reaction score
1,532
Location
Not Roy WA
That too, if you have one.

An analog (not digital) multimeter will also work, but the leads need to be made long enough.
 

1-ton

1/2 ton status
Premium Member
Joined
Apr 17, 2004
Posts
4,857
Reaction score
1,977
Location
Las Vegas, Nevada
Can also just take the air cleaner off and have your wife try and start it while you watch the injectors spray or not.
I do not like asking my wife to help me with my truck. Any time I ask her to help me with my truck she just starts whining, and saying things like "How long is this going to take?", or "I'm busy can't we do this later". I just gave up and don't bother asking anymore.
 

500$k5

wallet under gas pedal
Premium Member
GMOTM Winner
Joined
Apr 17, 2007
Posts
364
Reaction score
1,230
Location
Montrose, Colorado
In order. EGR Valve controller
Throttle position sensor (TPS)
Idle air control valve (IAC)
Exhaust Gas Recirculation Valve (EGR)
Electronic Spark Timing Module (EST)
The one above the egr in pic 6 is the Manifold Absolute Pressure Sensor (MAP)
 

500$k5

wallet under gas pedal
Premium Member
GMOTM Winner
Joined
Apr 17, 2007
Posts
364
Reaction score
1,230
Location
Montrose, Colorado
In your first post, you said it went "clunk". Did the injectors leak, and fill a cylinder full of fuel? Do you have spark, and fuel, but the plugs are too gas fouled to fire?
 

Wes Harden

3/4 ton status
Premium Member
Joined
May 28, 2005
Posts
5,406
Solutions
1
Reaction score
5,741
Location
Lake Havasu City AZ
Mentioned this back a few post. Not as clearly thou. Is what I am still thinking. I have had fuel fouled plugs stop an engine from starting until replaced with new.
 
Top Bottom