Yes, the blazer starts with a shot of starting fluid, I have yet to try jumping the primer fuel relay to keep the fuel pump.on and start it, but I'm sure it will also start that way, I just wanted to say something about the timing, I had the timing of the whole time, until I put a borescope camera In the #1 cyl. And then turned th ecrank untill.it was all the way TDC. The. I looked back at the crank k and it was actually on the mark to the leftside not the on in the rightside, if you were to be looking at the crankshaft. People online, Increase certified techs were saing to line the right mark up with a mark on the timing cover and the left mark with the one near the water pump, man were they wrong!!!!! So anyone who has an issue with not getting there blazer started, make sure to look and see that your #1 piston is TDC,! Then look at the crank for the closet line mark, Then line it up, also make sure your on the compression stroke, wich both valves will be closed. As far as the fuel pump ill test thos eports and wires this evening! Thanks again!!!!!!! You've been the best of help!!!!!!

 

Many a Blazer owner has chased their tail on the crank timing marks until they found out that the ring slipped on the balancer.

George

 

Hello again, 👋 so I tested the voltage at the fuel pump prime port, and I'm not getting any voltage ,no power there, with the key on, I used a test light, and even tested the a and c port, Grey and black wire at the fuel pump with key on, and no voltage at all, only 6 volts for the sending unit wires, so why dont I have any power? If I pull the fuel pump relay out and put a jumper wire in from the top left to the prime port, I can here the pump activate. I did this for a few seconds, the. Turn the key over and the blazer started and ran for a few seconds? I'm trying to figure out were is my power loss to the fuel pump when key is on?????? Any advice would help greatly!!!! Thanks

 

Just to be clear, the PCM only energizes the fuel pump relay and hence the fuel pump for a couple of seconds at key on so you have to watch for the voltage as soon as you turn on the ignition. If that's what your doing then we need to check if your are getting the energizing voltage from the PCM to the relay coil and that the other side of the coil has a solid ground. The fuel pump relay should be a 5 pin and hopefully the pin numbers are labeled on the underside of the relay because there are 2 types - A and B. If that's the case the pull the relay and look for pins 85 and 86. One of those should be the coil ground and the other should be the 12v energizing voltage to the relay from the PCM. We need to measure the voltage at key on at the relay socket..


George

 

Good morning, I purchased a new fuel pump relay from autozone and they gave me a 4 pun relay, it has 85 and 87 and 86 and 30 labeled, but you mentioned it should be a 5 pin relay? I also have a 5 pin, but will the 4 pin work? Or does it have to be the 5 pin? and can you flip the fuse, or does it have to be in a certain way? Thanks.

 

The 98 schematic shows a 5 pin with the 5th pin unused but that schematic also does not show where the priming tab is connected if you have one so I don’t know if the 5th pin is needed. On a 97 the priming tab is connected to the NC 5th terminal, 87a. On a 99 the priming tab is connected to 30 so the 5 pin is not needed, that year shows a 4 pin. The normal relay function should work with a 4 pin but the priming tab may or may not work if you have one. Also I don’t know if type A And Type B relays apply to 4 pins so I don’t know if that’s a factor here. If the truck ran OK at one time with the existing relay, make sure that pin 30 is the same on the new one.


George

 

I went and looked on Rock Auto and they also sell a four pin relay for a 98 and I trust them. Also I see that this relay does not use the industry standard automotive relay pin out so the whole type A/B thing does not apply. You just have to put it in the correct way.


George

 

So I measured the voltage at the relay terminal, I only got power by sticking the rest light in the right upper hand corner slot, it reads about 9 volts? I'm assuming the other ports are ground? Or the one diagnol from it. That's with key on, now if I take a wire and put one end in the top left corner port and one in the bottom left port, I can hear the pump rum, I've tried this and let it run a few seconds, then turned key over at blazer stared and ran a few seconds, so I'm just trying to figure out is it the relay? Or the pump?

 

At rest with the truck off, connect your meter ground to the negative battery post , remove the relay and tell me what the voltage readings are in the four relay pin sockets

George

 

I test it like you said, with negative lead at battery and positive lead of multimeter and I'm getting 13.38 volts only in the top right terminal port, all the other port holes show no voltage when I put the positive test cable in them. This is which key off. So does this means its getting power, it's probably a bad relay????