1988 BB Detroit Deisel 8V92 Wont Start

[Crabber82]

Okay, the adventure from the Bears Den continues and for all my "do it your selfer's" let me say that finding an mature mechanic was the best money I have spent and the one thing I can suggest.

So this all startered a little over a month ago with my 1988 starting in the storage lot just fine and then becoming very difficult to start in front of my home an hour later. Then not starting at all 4 days later resulting in a very expensive Tow back home.

After reading many post on three different blogs, I performed a thorough exploration of the entire fuel system.
So today I found out that the Bears Den has been trying to talk to me. Service Code 42 and Service Code 43. Synchronus Reference Sensor and Low Coolant Sensor. Now the coolant sensor code(43) is likely a bad sensor connection or corrosion because there is plenty of coolant in the system and the Bears Den has never overheated. But the SRS sensor (42) apparently works in cahoots with the TRS sensor and tells the engine control module that it is time to fire. Oh yeah!!! I forgot to mention that I am the proud owner of the first year that GM and Detroit Diesel partnered up and introduced DDEC I to the Detroit Diesel 92 series.

So here is the run down.
1. Turn the ignition to start position and wait for the Service Codes to Blink out at the engine light. This is a series of flashes and the codes are two digits each so have a pen and paper ready to take notes because if there are multiple codes it will signal each of them.
2. Chase down a copy of the code list and/or find a copy of the DDEC I (version one)trouble shooting guide. Thank you Wanderlodge Gurus for these documents.
3. In my case the trouble was the SRS code so I had to figure out which "leads" to explore with an Ohm meter to determine if it was sensor or wires to sensor. Was hoping it might be wires to sensor because prior to my Troubles I had replaced all the copper pipe in the Bear's Den with PEX and I considered the possibility that I could can broke a wire in the process. Hey, $5.00 and a few hours replacing a broken wire was better than the new sensors.

Now Most Any Service Manual is going to say disconnect Battery before proceeding. Sound advice.

4. Drain coolant system down 10-15 gallons so that you can remove the upper coolant plumbing with minimum mess.
5. Remove coolant plumbing.
6. Disconnect fuel lines going to DDEC fuel module mounted above engine. There are two lines. If you leave the one connect to backside of module you can use other end to close front port. Minimize risk of contaminants.
7. Disconnect two wire pigtails on right side of module. There is a 1/4 inch bolt in center of both. Be gentle this may be the first time they have ever been taken off so there may be resistance. Don't break it or your trouble will be many.
8. Remove four bolts securing DDEC module to bracket. You will be very happy you removed coolant plumbing.
9. There are two connectors hiding down here among a couple of fuel lines and wire bundles. These connectors are the first part of your prize. Carefully remove the connectors again being mindful that this is probably the first time the have been separated from their mate.
10. Now that the Sensor connector is exposed recheck the resistance of the sensor. If it checks good then the issue is wiring not sensor. To troubleshoot wiring all you need to do is "jumper" the line and then go back into the bedroom closet and check line resistance.

In my case it is indeed a faulty sensor. So I am off to the INTERWEB to find a sensor.

Updates to follow!!

[patticake]

Did you connect the two wires on the low coolant sensor to see if that is the problem? I had to replace mine twice in 5 year intervals. It will shut the bus down. That is code 42.
If you put the two wires together it will run. Of course, I have a DDEC II, and may be different.

[Crabber82]

This is a rewrite of an issue I ran into in a failure to start: I hope it helps

1988 Bluebird Wanderlodge Detroit Deisel 8V92 with DDEC ver I won’t start. Resolved!
Good evening Wanderlodge Owners,
My 1988 BB Wanderlodge with a Detroit Diesel 8V92 (turbo) is not "firing". For the 18 months that I have owned “The Bears Den” the engine has run faithfully until this week. The Bears Den has been started and run for 15-30 mins each month. Longer trips on several occasions.
After picking up the RV from storage lot, I drove to home and began preparation for a week of camping. When I went to start for departure the engine failed to start.

Strong batteries and good starter so engine cranked but no "fire". Yes plenty of fuel onboard. Yes fuel is fresh.
First thought...maybe fuel filter old and or dirty so I replaced both primary and secondary filters (oiled o-rings and filled filters with diesel). then bled lines and primed.
Cranked again but no fire. Tried "gas rag in breather filter" trick and got a little fire but not full ignition. Tried starter fluid in limited amount to same result. White smoke bellowed from exhaust.
I was at a loss and needed help...
This is not the way I like seeing The Bears Den.

Clearly there was a lack of fire so experience had me thinking no fuel. I removed fuel lines and tested for leaks and removed fuel pump to test pressure. While fuel pump was off it was suggested to make sure shaft that drives the pump was turning when engine cycles. Shaft turned properly.
After reading many post on three different blogs, I performed a thorough exploration of the entire fuel system.

Several young mechanics tried to work on The Bears Den so let me say that finding an mature mechanic was the best money I spent and the one thing I can suggest to all my “Bluebird’er’s”

I found out that The Bears Den has been trying to talk to me. Service Code 42 and Service Code 43. Synchronus Reference Sensor and Low Coolant Sensor. Now the coolant sensor code(43) is likely a bad sensor connection or corrosion because there is plenty of coolant in the system and the Bears Den has never overheated. But the SRS sensor (42) apparently works in cahoots with the TRS sensor and tells the engine control module that it is time to fire. Oh yeah!!! I forgot to mention that I am the proud owner of the first year that GM and Detroit Diesel partnered up and introduced DDEC I to the Detroit Diesel 92 series.
So here is the run down.
1. Turn the ignition to start position and wait for the Service Codes to Blink out at the engine light. This is a series of flashes and the codes are two digits each so have a pen and paper ready to take notes because if there are multiple codes it will signal each of them.
2. Chase down a copy of the code list and/or find a copy of the DDEC I (version one)trouble shooting guide.
3. In my case the trouble was the SRS code so I had to figure out which "leads" to explore with an Ohm meter to determine if it was sensor or wires to sensor. Was hoping it might be wires to sensor because prior to my Troubles I had replaced all the copper pipe in the Bear's Den with PEX and I considered the possibility that I could can broke a wire in the process. Hey, $5.00 and a few hours replacing a broken wire was better than the new sensors.

Now Most Any Service Manual is going to say disconnect Battery before proceeding. Sound advice.

4. Drain coolant system down 10-15 gallons so that you can remove the upper coolant plumbing with minimum mess.
5. Remove coolant plumbing.
6. Disconnect fuel lines going to DDEC fuel module mounted above engine. There are two lines. If you leave the one connect to backside of module you can use other end to close front port. Minimize risk of contaminants.
7. Disconnect two wire pigtails on right side of module. There is a 1/4 inch bolt in center of both. Be gentle this may be the first time they have ever been taken off so there may be resistance. Don't break it or your trouble will be many.
8. Remove four bolts securing DDEC module to bracket. You will be very happy you removed coolant plumbing.
9. There are two connectors hiding down here among a couple of fuel lines and wire bundles. These connectors are the first part of your prize. Carefully remove the connectors again being mindful that this is probably the first time the have been separated from their mate.
10. Now that the Sensor connector is exposed recheck the resistance of the sensor. If it checks good then the issue is wiring not sensor. To troubleshoot wiring all you need to do is "jumper" the line and then go back into the bedroom closet and check line resistance.

In my case it is indeed a faulty sensor. So off to the INTERWEB to find a sensor. The SRS/TRS sensor and on the 1988 Bluebird Detroit Deisel 8V92 this is a tandem package. If you replace one you are replacing both. These twins are located under the DDEC I Module that sits atop the center of the engine at the lift gate. See above on how to access the sensors.
My mechanic/tutor/teacher (Dan) warned me not to remove the bracket that the sensors are mounted in. The reality is this...these parts have probably not been accessed since their installation 30 years ago. You will be removing the mounting bracket from the engine. Just for a frame of reference, I am a pretty decent grease monkey and it took me about two hours per bolt to remove the bracket. The most important step before wrestling these two bolts. Measure all the spaces around the bracket with feeler gauges. “Etch” the location of the bracket and the bolts. Take lots of pictures!! The closer you can get this bracket back into position on reinstallation the greater the chances that you won’t mess up the timing!!
The OEM bolts are #5 hex heads but don’t fret. Visegrips and PB blaster and a fine bristle brush are your only hope of removing these things without snapping them off. Spray the entire area thoroughly with penetrating oil or your favorite brand of the same (PB blaster and 3 in 1 worked for me). Then leave it set over night. The next day spray again. Now take a steel or brass “toothbrush” (welding section of hardware store) and brush whatever exposed threads you can reach. Then begin the tedious task of removing the bolts. If you don’t “swear” your a better man than Me.
When you do finally get these out take them to a “Fastenall” store and replace them with a SAE fine thread bolt with a regular bolt head. You can thank me later.
Now find a machine shop to remove the “retaining bracket bolt. It’s a hex head bolt also throw it away and again replace it with a SAE bolt. You may have to retap hole so the exact size may vary.
Finally you are at the sensors. 30 years of corrosion and rust are about to teach you some new cuss words. But if you have access to a vise or a press it will help you tonget these suckers out.

IMPORTANT NOTE...before you commence the demolition measure exactly how far the sensors are poking out (nub distance) of the bracket. The more accurate the better. Now trim that nub off with a hacksaw and then press, bash or yell those sensors out!!! Don’t fret tearing them up. You are replacing them. I had neither a press or a vice so a small impact socket and a big hammer were my tools of choice.
What ever you do though...Do Not Break the Bracket.
Once the sensors are out you will need to recondition the holes and resting positions on the bracket. Yes corrosion has deformed this area and the new sensors are not just going to slip right back in. I used a round steal brush a drill and a round file. A lot of PB blaster and a fair amount of 3 in 1 oil.
Continuously check your progress and be super careful not to make the holes too large. You are only trying to get the rust and corrosion off the area. Once you have successfully cleaned the bracket back to where the sensors fit back in...put it all back together remembering to measure twice then tighten. I mounted sensors in bracket and set them at the “nub” distance. Then I mounted the bracket and made sure all the edge gaps were as close as practical using my etch marks and feeler gauges. Then as I tightened the bolts to there set position I double checked the bolt placement using a mirror and my pictures.
From this point on it is simply a reverse installation of anything you may have removed in the demolition. Word to the wise. Replace all those old hose clamps with new ones. It will be worth the $10 bucks. Replace your coolant. Replace, bleed and prime your fuel lines. Handy little trick I use now on that primer bulb atop RaCor...take a broad flat tool that is not sharp but has a handle and place between the breather pipe and the bulb and gently pump the primer bulb. It’s a heck of a lot easier than using your thumb.
Now that All is back in place... Take a knee give thanks to Bluebird or whatever deity that possessed you to take on this task. Stand up and turn the key.
Don’t be alarmed it won’t start the very first time but in my case it did start belching white smoke (good sign) and after a couple of attempts and no ether or gas rags The Bears Den roared to life.
Thank you Dan the Mechanic. Thank you all my supportive “Bluebird ‘ers”, Thank you Detroit Deisel Bloggers and thank you Sarah Jane for believing in me. The Bears Den Lives to ride another day!!

Took me two months to conquer..:but damn it feels good to know The Bears Den is road ready again

That most satisfying part? This coach is 30 years old and I am 54 and with support from the group and a new friend...I fixed it!!! Heck yeah! That is satisfying. Fellow Bluebird’ers? We have the power we can keep them going.

If you run into the same problem don’t hesitate to reach out.