hi all, and les, as per your advise am starting a new thread, i have a 2003 gmc jimmy 4.3 been working on it awhile now, mostly body and frame work. had it almost complete and all of a sudden it wont start, the day before no start it was hard to start, how it just cranks, but when i release the key from crank to run it seems to run backwards and blows smoke back in the air intake, or throttle body i guess you call it, i got 3 of the trucks so have parts i can rob and stuff so far i have did the prime in the throttle body, replaced the cam sensor on the distributer, the distributer, the cap and the rotor button, the coil and the pcm i think its called, i have spark yet the prime didnt work, have also replaced the crank sensor and the ignition switch..

thanks for all help guys

wade

 

Hi Wade. If you have swapped PCMs (computer on the passenger inner fender), then the theft deterrent will prevent it from running more than a couple of seconds unless it is programmed to your vehicle.

But since it won't start at all...… first let's make sure you have the distributor back in correctly. Download the attachment in this thread https://blazerforum.com/forum/articl...1996-a-101101/ and review the section/drawings about reinstalling the distributor. Do you understand it thoroughly how to put the engine on TDC#1 NOT TDC#4, and the difference between them? At that point you simply drop the distributor in with the rotor pointing to the #6 which is cast into the mounting flange for the distributor cap. If you have any questions about this, please ask the questions and we will help.

What years are your parts vehicles? Do you have a scanner? I can recommend OBD2 adapter/app for Android Phone for about $35 total. BAFX Bluetooth OBD2 adapter as sold on Amazon + for 2003 Blazer I would recommend Car Gauge Pro from Google Play. It will read the Cam Sensor Retard on the 1998+ Blazers.

 

hi Les,

i have that and going to do tomorrow, thanks for all your help, and i like the do one thing at a time approach, so thats first on list in the morning, if i get all this snow moved, holy crap

 

hi and didnt change the computer, the thing on attached to the coil, did both at same time

w

 

We're here for ya! But please know that I'm quite sensitive if people don't do all the things that I ask and try to shortcut or assume. In that case, you can still get help here - but just from someone else. Sometimes that can ever be better as I don't have a lock on all valid info!! So we can see how we work together on your problem. If you have an Android phone or tablet, please go ahead and get the stuff for the scanner. I guarantee you will be using it eventually.

 

That would be the ignition module.

The other thing I would like you to do is to rig up a spark plug on a plug wire from another vehicle, open the plug gap up to about 1/8" or 3/16", plug the wire into the ignition coil, and clamp the metal base of the spark plug to something metal on the engine with a pair of vice grips. Then watch for strong steady blue sparks as the engine cranks.

 

hi i have an iphone 6 i think it is, i will look into the scan things tonight, i certainly need them, and i will study that link as well to ensure it is done properly, and get an understanding of the difference between tdc 1 or 4, cause right now i dont, will those phone scanners do the same as the scanners that can do the relearns, bleed the abs and things like that, or should i wait and save for the better one, there is no renting or borrowing one around here and it wil be a min of 200 bucks a pop to take it in

wade

 

For iPhone, there is an app called Dash Command that will work with a WiFi OBD2 adapter (not Bluetooth). It comes for Android or for iPhone. Dash Command ($10) will also work well with your Blazer for cam sensor retard (this is what few apps will do), but it requires an additional $10 license for each vehicle where you want the enhanced GM PIDs (and you do). That said, the Dash Command interface is more intuitive than Car Gauge Pro and the functions are filtered better - just costs more. I have no experience with the BAFX Wifi OBD2 adapter, but their Bluetooth one sure is good and fast too. I have had mine for over 5 years.

Car Gauge Pro can read the ABS codes but no PIDs or brake bleeding. Cheapest scanner I have found for brake bleeding and crank sensor relearns on the Blazer is the Vident I-link-400 - a hand-held at around $161 on Amazon. I'm very impressed with it (but don't drop it - it is made of pure Chinesium so appears a bit fragile)

I have a lot of different scanners and my opinion is to use Car Gauge Pro for 1998-2004 GM vehicles if you have an Android. Dash Command if you have an iPhone on 1996-2004 Blazers. If you need more than the phone apps will give you then jump to the Vident I-link 400. Note the Vident does not do anything with 4WD. I like to have different scanners for different things, and admittedly I like to play with them.

I have:
Car Gauge Pro (Android) $9 - cam sensor retard but does only 1998-2004 Blazer
Dash Command (Android) $10 + $10 for enhanced PIDs for each vehicle - cam sensor retard and 1996-2004 Blazer
Torque Pro (Android) $6 - no cam sensor retard but great at graphing multiple PIDs in same screen.
Vident I-link 400 (Handheld) $161 - does relearns + brake bleed + more
OBD2 Wiz (Windows) free with OBDlinkSX USB OBD2 adapter - very basic stuff
Scan XL Pro w/GM enhanced PIDs (Windows) $150 - cam sensor retard + ABS
HP Tuners VCM Scanner (Windows) $350 - does relearns but not brake bleed.

I find the Bluetooth OBD2 adapter is very convenient to carry in the glove box since I always have my phone on me.

 

i will do that tomorrow, as well as the disrtibuter, and let you know how it works
w

 

Firing order is 1-6-5-4-3-2. Engine is 4-stroke (of the piston going up/down). So each cylinder fires every second revolution of the crankshaft.

Simply put, during one alignment of the balancer marks you are TDC#1. Turn the crankshaft 1 revolution and you are TDC#4. Turn it one more revolution and you are back to TDC#1.

You tell which one it is by feeling for compression at the #1 spark plug hole (front, drivers side) as the engine is being rotated (tiny taps with the starter - you need a helper or a remote starter button). The very next time the marks on the balancer align, then you are at TDC#1