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I have completed a swap of a Blueprint 383 stroker engine (436HP - details in my profile) into my 1988 convertible. The donor car was a 1986 coupe and the engine came with headers, stock TPI, injectors that appear to be 20# (stamped with 280150556 on them). During the swap I kept my 1988 wiring harness (I had different AC setup than the 86) and kept the 86 computer, TPI, etc. I put 3" pipes back from my headers straight to dual exhaust. Engine sounds amazing, but isn't running great yet - from what I read I can get pretty good performance with the stock TPI, and I love the stock TPI look so want to learn how to tune what I have. Fuel burn smells rich at idle and I get occasional misses at all speeds. I've been able to datalog using datacat for a 20 minute drive (output uploaded here), and ordered the Burn 2 from Moates which should be here this weekend. Engine codes are clear on this run, but I do get the occasional code 36 for Mass Air Flow Sensor Burn-Off Function Fault. From the scan data the INT hover around 128, but BLMs at all cells are reading lean - but I feel its running very rich from the fuel smell at idle. Any suggestions where to start looking?
Not a whole lot to go by in this log, but its a start. BLM is a bit lean (140-146), but not terribly so. The idle appears to be hanging high with IAC at zero counts. MAF is responding to tps as it should. Would like to see prom id, lv8, injector pw, O2 sensor behavior, mph, etc.
Is this a factory bin file? Has there been any tuning done so far? 20 lb/hr injectors a bit small for the application (if correct). Any ethanol in the fuel, fuel pressure, initial advance still 6 degrees?
Note: I have DataCat, so the dcf files will be more helpful to me than limited bits of exported data.
Thanks everyone for the quick replies. I posted the full DCF bin file here: https://drive.google.com/file/d/16QK...ew?usp=sharing This is not a factory bin, the EPROM is tuned and came with the donor car, I can't read the bin until this weekend when I get my Moates burn 2. I'm running premium fuel and near sea level elevation (I'm in Austin TX). The base timing set at 13 (thats what Blueprint calls for) but with the knocks showing on hard acceleration, I can back that off to 10-11 to see if it helps. Compression ratio is 10:1 on this. On the injectors I can't see the brand, but the numbers on it say 280150556 which seem to be Bosch 20# -but I have no way to know if they were redone or just the standard Bosch part. I am real curious when I read the bin, what is in there.
From the dcf (data file) it looks like a lightly re-tuned copy of a 1989 ARAR based bin. Minor spark advance tuning, no apparent PE spark advance, reduced fan on/off temperature, nothing special really. Spark advance is set up for 6 degree initial advance. I would suggest setting the timing to 6 degrees and trying to get a handle on the knock first.
Note: it is pulling more timing than the 7 degree offset that was added by setting initial advance from 6 to 13 degrees. Could be false knock, but try reduced advance along with good fuel (93 octane) to see what happens.
You are definitely going to need bigger injectors. I would suggest replacing them before spending a bunch of time tuning with 20lb injectors. I would suggest 30lb for a 383. I also would recommend high flow runners and base otherwise your 400 horse motor will be way less. It will have lots of torque though which will still be fun.
Thanks for the advice and questions. I am not running an oiled air filter, its the stock 1988 air filter. I do think I'll need bigger injectors if these are just 20#. I set the base timing back to 6 per tequilaboy's advice and made another run another run today. I still got knocks under hard acceleration, but less. Its a shorter drive but got to closed loop. Here is the datacat DCF file https://drive.google.com/file/d/13y6...ew?usp=sharing
You are definitely going to need bigger injectors. I would suggest replacing them before spending a bunch of time tuning with 20lb injectors. I would suggest 30lb for a 383. I also would recommend high flow runners and base otherwise your 400 horse motor will be way less. It will have lots of torque though which will still be fun.
For 30#, I'd recommend the 280155759. The datasheet for them is attached.... you'll want to put the voltage offsets from this datasheet.
As long as they're genuine Bosch and not knock-off's that are "compatible" or "interchangangeable" with the Bosch injectors.
Alternatively, you can also get them from Southbay Fuel Injectors. Tell them you want the particular Bosch p/n 28015759. Their products and customer service is top notch.
The reason I personally selected those for my car was due to a bad experience with knock-off's from another company where there was no datasheet available for them. I found that these 759's were also used by Ford Motorsport and Ford put their own P/N on them and then published an official datasheet.
In addition...
On $8D (1990-91) as well as $DA3 (1992-93) and $EE (1994-95) there's also a table called Low Pulse Width Injector Offset vs Base Pulse Width. That table gets zeroed out typically with Bosch-III's since they're so much more efficient than the old Multec's at low pulse widths.
Oddly enough, I don't see a corresponding table like that in my $6E xdf file (your '88 will be $6E). If you, or your tuner sees a table like that, you should zero it out.
I just took a longer run and was able to get some good take offs recorded, seems the duty cycle is > 100% at times which seems to confirm I am being limited by fuel... I have the DCF file uploaded as well https://drive.google.com/file/d/13kK...ew?usp=sharing
I bought these to replace some Accel injectors that were in my car at the request of my tuner: https://www.ebay.com/itm/291100752546
My car is running OK/better now but will be properly tuned next week. The seller seems knowledgeable and will answer his phone and any questions you may have.
That injector histogram is a bit misleading. There are only 3 samples in the log that push the duty cycle over 100%. See frames 1732,4524 and 5268. These are LV8 AE events that occurred at already high load and high injector dc and are not really typical. The injectors are borderline, but they are sufficient for the most part at the current power level and rpm according to the data. You could simply increase the fuel pressure to provide some additional margin or try and avoid high load AE events.
Looking into those injectors, but I think I'll hold off for the minute as it will take quite a days work to pull the TPI to change them. I want to learn more about this engine/TPI mix to see what I can get as is as I do like the torque that is there. If I need the bigger injectors, may as well get a ported TPI intake at the same time.... Anyhow today my Burn2 showed up and I was able to pull the bin (attached) and it is a $6E bin.
Trying to see what to modify for the max airflow vs RPM table, is there harm in setting that airflow to 200 for 2800 and 3200 RPM and up to 255 for 4000 RPM and above?
Also I noticed this tune takes about 3 seconds of cranking to fire, vs a stock tune from my 88 fires right up, is there mods I should do to the Crank Fuel tables for this?
Lastly, is there a setting to remove the overdrive light on the dash, or is that something all $6E chips running on an 88 Vette will do regardless?
I would add at least 15-20 gm/sec for 1,600 rpm and above to avoid limiting as it is now and to provide some additional headroom for cold weather conditions. There is not much harm in going even higher, but not much benefit in doing so either. This table mainly protects for over-fueling during failure modes such as an open circuit or high signal voltage prior to failure detection, an overly inflated maf calibration/bad tuning or when running on the default airflow calculation during an active MAF failure (Code 33 or 34).
$6E delays crank fueling for the first 8 distributor reference pulses for cleaner cold start emissions, so it may require more cranking time as compared with $32B. The OD lamp is a known issue when running a 1989 $6E based bin in an 87-88 car with the OD indicator in the dash. I did some work to resolve this issue about 20 years ago, but will need to do some digging to refresh my memory.
Bin notes: There are some very strange values here and there in your bin which I don't really understand yet. I don't know if some values have been relocated to different addresses, but some things look very peculiar.
For example, the mask id and mask id comparison bytes are both $6F instead of $6E. Someone may have built a custom mask for some unknown reason. I will try and get a better understanding of some of the more bizarre settings, but you may want to consider starting over with a good known stock bin for your 2.73 gear vert (like ARAS). Do you know the source of this bin or who the original hacker/tuner was?
I prefer to use $32B for the earlier cars, but many seem to like $6E especially for auto trans cars. The only real benefit of $6E is highway mode fueling which can provide minor fuel economy gains.
Last edited by tequilaboy; Jan 4, 2025 at 01:41 AM.
Are you certain that the bin was read properly with correct device type settings? The reason I ask is that many, many bytes differ from their expected values by an offset of 1 including about 4,000 bytes in the Algo/program region with addresses starting at 710. I'm comparing with respect to a copy of ARAP. Something screwy about this bin. Only about 400 bytes have been changed in the Calibration/data region (from addresses 0 to 709), but many of these also only differ from their standard/expected values by 1 increment. Excrement may the the more appropriate term here.
Might want to try reading the eeprom (or eprom) again to see if both copies agree/verify against each other.
Thanks for the deep read of this tune, unfortunately I don't know the original tuner, but it doesn't run well in the car either so I'm not dying to "save" the tune that came on this chip. I did read it several times and the bin files are the same, so I think at this point its going to be easier to start with a new bin. I like the suggestion to go with a $32B - I'll use the $32B that I have in my prior 88 computer, then I can understand it all better and get this dialed in both open loop and closed loop.
I'll modify my $32B bin for my injector size and idle speeds and take a long run today and will post back.
Tuning suggestions for Blueprint 383 stroker
